Minimize Copernicus: Sentinel-2

Copernicus: Sentinel-2 — The Optical Imaging Mission for Land Services

Space Segment   Launch   Mission Status   Sensor Complement   Ground Segment   References

Sentinel-2 is a multispectral operational imaging mission within the GMES (Global Monitoring for Environment and Security) program, jointly implemented by the EC (European Commission) and ESA (European Space Agency) for global land observation (data on vegetation, soil and water cover for land, inland waterways and coastal areas, and also provide atmospheric absorption and distortion data corrections) at high resolution with high revisit capability to provide enhanced continuity of data so far provided by SPOT-5 and Landsat-7. 1) 2) 3) 4) 5) 6) 7) 8)

Copernicus is the new name of the European Commission's Earth Observation Programme, previously known as GMES (Global Monitoring for Environment and Security). The new name was announced on December 11, 2012, by EC (European Commission) Vice-President Antonio Tajani during the Competitiveness Council.

In the words of Antonio Tajani: "By changing the name from GMES to Copernicus, we are paying homage to a great European scientist and observer: Nicolaus Copernicus (1473-1543). As he was the catalyst in the 16th century to better understand our world, so the European Earth Observation Programme gives us a thorough understanding of our changing planet, enabling concrete actions to improve the quality of life of the citizens. Copernicus has now reached maturity as a programme and all its services will enter soon into the operational phase. Thanks to greater data availability user take-up will increase, thus contributing to that growth that we so dearly need today."

Table 1: Copernicus is the new name of the former GMES program 9)

The overall GMES user requirements of the EU member states call for optical observation services in the areas of Global Climate Change (Kyoto Protocol and ensuing regulations), sustainable development, European environmental policies (e.g. spatial planning for Soil Thematic Strategy, Natura 2000 and Ramsar Convention, Water Framework Directive), European civil protection, common agricultural policy, development and humanitarian aid, and EU Common Foreign & Security Policy.

To meet the user needs, the Sentinel-2 satellite data will support the operational generation of the following high level products like:

• Generic land cover, land use and change detection maps (e.g. CORINE land cover maps update, soil sealing maps, forest area maps)

• Maps of geophysical variables (e.g. leaf area index, leaf chlorophyll content, leaf water content).

The mission is dedicated to the full and systematic coverage of land surface (including major islands) globally with the objective to provide cloud-free products typically every 15 to 30 days over Europe and Africa. To achieve this objective and to provide high mission availability, a constellation of two operational satellites is required, allowing to reach a 5-day geometric revisit time. The revisit time with only one operational satellite as it will be the case at the beginning of the deployment of the system is 10 days. - In comparison, Landsat-7 provides a 16-day geometric revisit time, while SPOT provides a 26-day revisit, and neither of them provides systematic coverage of the overall land surface.

The following list summarizes the top-level system design specifications derived from the user requirements:

• Sentinel-2 will provide continuity of data for services initiated within the GSE (GMES Service Element) projects. It will establish a key European source of data for the GMES Land Fast Track Monitoring Services and will also contribute to the GMES Risk Fast Track Services.

• The frequent revisit and high mission availability goals call for 2 satellites in orbit at a time, each with a 290 km wide swath using a single imaging instrument

• Continuous land + islands carpet mapping imaging within the latitude range of -56º to +83º (the selected orbit excludes imagery from Antarctica)

• 10 m, 20 m, and 60 m spatial resolution (in the VNIR to SWIR spectral range) to identify spatial details consistent with 1 ha MMU (Minimum Mapping Unit)

• An accurate geolocation (< 20 m) of the data is required (without GCPs) and shall be produced automatically to meet the timeliness requirements. The geolocation accuracy of Level 1 b imagery data w.r.t. WGS-84 (World Geodetic System - 1984) reference Earth ellipsoid of better than 20 m at 2σ confidence level without need of any ground control points is required.

• Very good radiometric image quality (combination of onboard absolute and on ground vicarious calibration).

• The mission lifetime is specified as 7.25 years and propellant is to be sized for 12 years, including provision for de-orbiting maneuvers at end-of-life.

• 2 weeks of satellite autonomy and maximum decoupling between flight operations and mission exploitation

Fast Track Service (Land Monitoring Core Services)

Compliance of the Sentinel-2 system

Geographic coverage

All land areas/islands covered (except Antarctica)

Geometrical revisit

5 days revisit cloud free fully in line with vegetation changes

Spectral sampling

Unique set of measurement/calibration bands

Service continuity

Sentinel-2A launch in 2014: the mission complements the SPOT and Landsat missions.

Spatial resolution

< 1 ha MMU (Minimum Mapping Unit) fully achievable with 10 m

Acquisition strategy

Systematic push-broom acquisitions, plus lateral mode capability for emergency events monitoring

Fast Track Service (Emergency Response Core Service)

Compliance of the Sentinel-2 system

Spatial resolution down to 5 m

Reference/damage assessment maps limited to the 10m SSD (Spatial Sampling Distance)

Accessibility/timeliness down to 6 hrs offline & 24hrs in NRT

Fully compliant (retrieval of already archived reference data in < 6 hrs, and delivery of data after request in NRT in 3 hrs for L1c)

Table 2: Sentinel-2 fast track service compliance to land user requirements

To provide operational services over a long period (at least 15 years following the launch of the first satellites), it is foreseen to develop a series of four satellites, with nominally two satellites in operation in orbit and a third one stored on ground as back-up.

 

In partnership: The Sentinel-2 mission has been made possible thanks to the close collaboration between ESA, the European Commission, industry, service providers and data users. Demonstrating Europe's technological excellence, its development has involved around 60 companies, led by Airbus Defence and Space in Germany for the satellites and Airbus Defence and Space in France for the multispectral instruments. 10)

The mission has been supported in kind by the French space agency CNES to provide expertise in image processing and calibration, and by the German Aerospace Center DLR that provides the optical communication payload, developed by Tesat Spacecom GmbH.

This piece of technology allows the Sentinel-2 satellites to transmit data via laser to satellites in geostationary orbit carrying the European Data Relay System (EDRS). This new space data highway allows large volumes of data to be relayed very quickly so that information can be even more readily available for users.

Seven years in the making, this novel mission has been built to operate for more than 20 years. Ensuring that it will meet users' exacting requirements has been a challenging task. Developing Sentinel-2 has involved a number of technical challenges, from early specification in 2007 to qualification and acceptance in 2015.

The satellite requires excellent pointing accuracy and stability and, therefore, high-end orbit and attitude control sensors and actuators. The multispectral imager is the most advanced of its kind, integrating two large visible near-infrared and shortwave infrared focal planes, each equipped with 12 detectors and integrating 450,000 pixels.

Pixels that may fail in the course of the mission can be replaced by redundant pixels. Two kinds of detectors integrate high-quality filters to isolate the spectral bands perfectly. The instrument's optomechanical stability must be extremely high, which has meant the use of silicon carbide ceramic for its three mirrors and focal plane, and for the telescope structure itself.

The geometric performance requires strong uniformity across the focal planes to avoid image distortion. The radiometric performance excluded any compromise regarding stray light, dictating a tight geometry and arrangement of all the optical and mechanical elements. The instrument is equipped with a calibration and shutter mechanism that integrates a large spectralon sunlight diffuser.

Each satellite has a high level of autonomy, so that they can operate without any intervention from the ground for periods of up to 15 days. This requires sophisticated autonomous failure analysis, detection and correction on board.

The ‘carpet mapping' imaging plan requires acquisition, storage and transmission of 1.6 TB per orbit. This massive data blast results from the combination of the 290 km swath with 13 spectral channels at a spatial resolution as high as 10 m.

In addition, the optical communication payload using the EDRS data link is a new technology that will improve the amount and speed of data delivery to the users. This was very recently demonstrated by Sentinel-1A, which also carries an optical communication payload.

Land in focus: Ensuring that land is used sustainably, while meeting the food and wood demands of a growing global population – a projected eight billion by 2020 – is one of today's biggest challenges. The Copernicus land service provides information to help respond to global issues such as this as well as focusing on local matters, or ‘hotspots', that are prone to specific challenges.

However, this service relies on very fast revisit times, timely and accurate satellite data in order to make meaningful information available to users – hence, the role of Sentinel-2. Through the service, users will have access to information about the health of our vegetation so that informed decisions can be made – whether about addressing climate change or how much water and fertilizer are needed for a maximum harvest.

Sentinel-2 is able to distinguish between different crop types and will deliver timely data on numerous plant indices, such as leaf area index, leaf chlorophyll content and leaf water content – all of which are essential to accurately monitor plant growth. This kind of information is essential for precision farming: helping farmers decide how best to nurture their crops and predict their yield.

While this has obvious economic benefits, this kind of information is also important for developing countries where food security is an issue. The mission's fast geometric revisit of just five days, when both satellites are operational, and only 10 days with Sentinel-2A alone, along with the mission's range of spectral bands means that changes in plant health and growth status can be easily monitored.

Sentinel-2 will also provide information about changes in land cover so that areas that have been damaged or destroyed by fire, for example, or affected by deforestation, can be monitored. Urban growth also can be tracked.

The Copernicus services are managed by the European Commission. The five ‘pan-European' themes covering 39 countries are addressed by the land service, including sealed soil (imperviousness), tree cover density, forest type, and grasslands. There is currently insufficient cloud-free satellite data in high resolution with all the necessary spectral bands that cover Europe fast enough to monitor vegetation when it is growing rapidly in the summer. Sentinel-2 will fill this gap.

This multi-talented mission will also provide information on pollution in lakes and coastal waters at high spatial resolution and with frequent coverage. Frequent coverage is also key to monitoring floods, volcanic eruptions and landslides. This means that Sentinel-2 can contribute to disaster mapping and support humanitarian aid work.

Leading edge: The span of 13 spectral bands, from the visible and the near-infrared to the shortwave infrared at different spatial resolutions ranging from 10 to 60 m on the ground, takes global land monitoring to an unprecedented level.

The four bands at 10 m resolution ensure continuity with missions such as SPOT-5 or Landsat-8 and address user requirements, in particular, for basic land-cover classification. The six bands at 20 m resolution satisfy requirements for enhanced land-cover classification and for the retrieval of geophysical parameters. Bands at 60 m are dedicated mainly to atmospheric corrections and cirrus-cloud screening.

In addition, Sentinel-2 is the first civil optical Earth observation mission of its kind to include three bands in the ‘red edge', which provide key information on the vegetation state.

Thanks to its high temporal and spatial resolution and to its three red edge bands, Sentinel-2 will be able to see very early changes in plant health. This is particularly useful for the end users and policy makers to detect early signs of food shortages in developing countries (Ref. 10).

Sentinel-2A launch

June 23, 2015, by Vega from Kourou, French Guiana

Sentinel-2B launch

March 2017, by Vega from Kourou, French Guiana

Orbit

Sun-synchronous at altitude 786 km, Mean Local Solar Time at descending node: 10:30 (optimum Sun illumination for image acquisition)

Geometric revisit time

Five days from two-satellite constellation (at equator)

Design life

Seven years (carries consumable for 12 years: 123 kg of fuel including end of life deorbiting)

MSI (Multispectral Imager)

MSI covering 13 spectral bands (443–2190 nm), with a swath width of 290 km and a spatial resolution of 10 m (four visible and near-infrared bands), 20 m (six red edge and shortwave infrared bands) and 60 m (three atmospheric correction bands).

Receiving stations

MSI data: transmitted via X-band to core Sentinel ground stations and via laser link through EDRS.
Telecommand and telemetry data: transmitted from and to Kiruna, Sweden

Main applications

Agriculture, forests, land-use change, land-cover change. Mapping biophysical variables such as leaf chlorophyll content, leaf water content, leaf area index; monitoring coastal and inland waters; risk and disaster mapping

Mission

Managed, developed, operated and exploited by various ESA establishments

Funding

ESA Member States and the European Union

Prime contractors

Airbus Defence & Space Germany for the satellite, Airbus Defence & Space France for the instrument

Cooperation

CNES: Image quality optimization during in-orbit commissioning
DLR: Optical Communication Payload (provided in kind)
NASA: cross calibrations with Landsat-8

Table 3: Facts and figures

 


 

Space segment:

In April 2008, ESA awarded the prime contract to Airbus Defence and Space (former EADS-Astrium GmbH) of Friedrichshafen, Germany to provide the first Sentinel-2A Earth observation satellite. In the Sentinel-2 mission program, Astrium is responsible for the satellite's system design and platform, as well as for satellite integration and testing. Astrium Toulouse will supply the MSI (MultiSpectral Instrument), and Astrium Spain is in charge of the satellite's structure pre-integrated with its thermal equipment and harness. The industrial core team also comprises Jena Optronik (Germany), Boostec (France), Sener and GMV (Spain). 11) 12) 13) 14)

In March 2010, ESA and EADS-Astrium GmbH signed another contract to build the second Sentinel-2 (Sentinel-2B) satellite, marking another significant step in the GMES program. 15) 16) 17)

Sentinel-2 uses the AstroBus-L of EADS Astrium, a standard modular ECSS (European Cooperation for Space Standards) compatible satellite platform compatible with an in-orbit lifetime of up to 10 years, with consumables sizeable according to the mission needs. The platform design is one-failure tolerant and the standard equipment selection is based on minimum Class 2 EEE parts, with compatibility to Class 1 in most cases. The AstroBus-L platform is designed for direct injection into LEO (Low Earth Orbit). Depending on the selection of standard design options, AstroBus-L can operate in a variety of LEOs at different heights and with different inclinations. An essential feature of AstroBus-L is the robust standard FDIR (Failure Detection, Isolation and Recovery) concept, which is hierarchically structured and can easily be adapted to specific mission needs.

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Figure 1: Artist's rendition of the Sentinel-2 spacecraft (image credit: ESA, Airbus DS)

The satellite is controlled in 3-axes via high-rate multi-head star trackers, mounted on the camera structure for better pointing accuracy and stability, and gyroscopes and a GNSS receiver assembly. The AOCS (Attitude and Orbit Control Subsystem) comprises the following elements: 18)

• A dual frequency GPS receiver (L1/L2 code) for position and time information

• A STR (Star Tracker) assembly for precise attitude information (use of 3 STRs)

• A RMU (Rate Measurement Unit) for rate damping and yaw acquisition purposes

• A redundant precision IMU (Inertial Measurement Unit) for high-accuracy attitude determination

• Magnetometers (MAG) for Earth magnetic field information

• CESS (Coarse Earth Sun Sensors) for coarse Earth and Sun direction determination

• 4 RW (Reaction Wheels) and 3 MTQ (Magnetic Torquers)

• RCS (Reaction Control System) a monopropellant propulsion system for orbit maintenance with 1 N thrusters

The different tasks of the AOCS are defined the following modes:

• Initial Acquisition and Save Mode (rate damping, Earth acquisition, yaw acquisition, steady-state)

• Normal Mode (nominal and extended observation)

• Orbit Control Mode (in- and out-of-plane ΔV maneuvers).

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Figure 2: Overview of the AOCS architecture (image credit: EADS Astrium)

The geolocation accuracy requirements of < 20 m for the imagery translate into the following AOCS performance requirements as stated in Table 4.

Attitude determination error (onboard knowledge)

≤ 10 µrad (2σ) per axis

AOCS control error

≤ 1200 µrad (3σ) per axis

Relative pointing error

≤ 0.03 µrad/1.5 ms (3σ); and ≤ 0.06 µrad/3.0 ms (3σ)

Table 4: AOCS performance requirements in normal mode

For Sentinel-2 it was decided to mount both the IMU and the star trackers on the thermally controlled sensor plate on the MSI. So the impact of time-variant IMU/STR misalignment on the attitude performance can be decreased to an absolute minimum. Furthermore, the consideration of the time-correlated star tracker noises by covariance tuning was decided.

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Figure 3: Sentinel-2 spacecraft architecture (image credit: Astrium GmbH)

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Figure 4: Block diagram of the Sentinel-2 spacecraft (image credit: EADS Astrium)

The EPS (Electric Power Subsystem) consists of:

• Solar Array (one deployable and rotatable single wing with three panels). Total array area of 7.1 m2. Use of 2016 triple junction GaAs solar cells with integrated diode. Total power of 2300 W (BOL) and 1730 W (EOL). The mass is < 40 kg.

• SADM (Solar Array Drive Mechanism) for array articulation. Use of a two phase stepper motor with µ-stepping to minimize parasitic distortions during MSI operation, motor step angle 1.5º. Mass of < 3.2 kg.

• PCDU (Power Control and Distribution Unit). PCDU with one unregulated 28 V ±4 V main power bus. Mass of < 21.6 kg; the in-orbit life is 12.25 years.

• Li-ion batteries with 8 cells in series. Total capacity of 102 Ah @ EOL. Mass = 51 kg.

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Figure 5: Block diagram of the electrical power subsystem (image credit: EADS Astrium)

The OBC is based on the ERC32 PM (Processor Module) architecture. The PLDHS (Payload Data Handling System) provides source data compression from 1.3 Gbit/s to 450 Mbit/s [state-of-the-art lossy compression (wavelet transform)].

The spacecraft mass is ~ 1200 kg, including 275 kg for the MSI instrument, 35 kg for the IR payload (optional) and 80 kg propellant (hydrazine). The S/C power is 1250 W max, including 170 W for the MSI and < 100 W for the IR payload. The spacecraft is designed for a design life of 7.25 years with propellant for 12 years of operations, including deorbiting at EOL (End of Life).

Spacecraft mass, power

~1200 kg, 1700 W

Hydrazine propulsion system

120 kg hydrazine (including provision for safe mode, debris avoidance and EOL orbit decrease for faster re-entry)

Spacecraft design life

7 years with propellant for 12 years of operations

AOCS (Attitude and Orbit Control Subsystem)

- 3-axis stabilized based on multi-head Star Tracker and fiber optic gyro
- A body pointing capability in cross-track is provided for event monitoring

- Accurate geo-location (20 m without Ground Control Points)

RF communications

X-band payload data downlink at 560 Mbit/s
S-band TT&C data link (64 kbit/s uplink, 2 Mbit/s downlink) with authenticated/encrypted commands

Onboard data storage

2.4 Tbit, and data formatting unit (NAND-flash technology as baseline) that supplies the mission data frames to the communication subsystems.

Optical communications

LCT (Laser Communication Terminal) link is provided via EDRS (European Data Relay Satellite)

Table 5: Overview of some spacecraft parameters

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Figure 6: Schematic view of the deployed Sentinel-2 spacecraft (image credit: EADS Astrium)

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Figure 7: The Sentinel-2 spacecraft in launch configuration (image credit: ESA)

Payload data are being stored in NAND flash memory technology SSR (Solid State Recorder) based on integrated CoReCi (Compression Recording and Ciphering) units of Airbus DS, available at various capacities. The CoReCi is an integrated image compressor, mass memory and data ciphering unit designed to process, store and format multi-spectral video instrument data for the satellite downlink. The mass memory utilizes high performance commercial Flash components, ESA qualified and up-screened for their use in space equipment. This new Flash technology allows mass and surface area used in the memory to be reduced by a factor of nearly 20 when compared with the former SD-RAM (Synchronous Dynamic Random Access Memory) based equipment. The first CoReCi unit has been successfully operating on SPOT-6 since September 2012. Sentinel-2A is carrying a CoReCi unit. 19) 20)

The MRCPB (Multi-Résolution par Codage de Plans Binaires) compression algorithm used is a wavelet transform with bit plane coding (similiar to JPEG 2000). This complex algorithm is implemented in a dedicated ASIC, with speeds of up to 25 Mpixel/s. Alternatively this unit can be supplied with a CCSDS compression algorithm using a new ASIC developed with ESA support. The ciphering is based on the AES algorithm with 128 bit keys. The modularity of the design allows the memory capacity and data rate to be adapted by adjusting the number of compressor and memory boards used.

 

Development status:

• February 27, 2017: The ninth Vega light-lift launcher is now complete at the Spaceport, with its Sentinel-2B Earth observation satellite installed atop the four-stage vehicle in preparation for a March 6 mission from French Guiana. 21)

• January 12, 2017: Sentinel-2B arrived at Europe's spaceport in Kourou, French Guiana on 6 January 2017 to be prepared for launch. After being moved to the cleanroom and left for a couple of days to acclimatise, cranes were used to open the container and unveil the satellite. Over the next seven weeks the satellite will be tested and prepared for liftoff on a Vega rocket. 22)

• November 15, 2016: Sentinel-2B has successfully finished its test program at ESA/ESTEC in Noordwijk, The Netherlands. The second Sentinel-2 Airbus built satellite will now be readied for shipment to the Kourou spaceport in French Guiana begin January 2017. It is scheduled for an early March 2017 lift-off on Vega. 23)

- Offering "color vision" for the Copernicus program, Sentinel-2B like its twin satellite Sentinel-2A will deliver optical images from the visible to short-wave infrared range of the electromagnetic spectrum. From an altitude of 786 km, the 1.1 ton satellite will deliver images in 13 spectral bands with a resolution of 10, 20 or 60 m and a uniquely large swath width of 290 km.

• June 15, 2016: Airbus DS completed the manufacture of the Sentinel-2B optical satellite; the spacecraft is ready for environmental testing at ESA/ESTEC. The Sentinel-2 mission, designed and built by a consortium of around 60 companies led by Airbus Defence and Space, is based on a constellation of two identical satellites flying in the same orbit, 180° apart for optimal coverage and data delivery. Together they image all Earth's land surfaces, large islands, inland and coastal waters every five days at the equator. Sentinel-2A was launched on 23 June 2015, its twin, Sentinel-2B, will follow early next year. 24)

- The Sentinel-1 and -2 satellites are equipped with the Tesat-Spacecom's LCT (Laser Communication Terminal). The SpaceDataHighway is being implemented within a Public-Private Partnership between ESA and Airbus Defence and Space.

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Figure 8: Sentinel-2B being loaded at Airbus Defence and Space's satellite integration center in Friedrichshafen, Germany (image credit: Airbus DS, A. Ruttloff)

• April 27, 2015: The Sentinel-2A satellite on Arianespace's next Vega mission is being readied for pre-launch checkout at the Spaceport, which will enable this European Earth observation platform to be orbited in June from French Guiana. — During activity in the Spaceport's S5 payload processing facility, Sentinel-2A was removed from the shipping container that protected this 1,140 kg class spacecraft during its airlift from Europe to the South American launch site. With Sentinel-2A now connected to its ground support equipment and successfully switched on, the satellite will undergo verifications and final preparations for a scheduled June 11 liftoff. 25)

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Figure 9: Sentinel-2A is positioned in the Spaceport's S5 payload processing facility for preparation ahead of its scheduled June launch on Vega (image credit: Arianespace)

• April 23, 2015: The Sentinel-2A satellite has arrived safe and sound in French Guiana for launch in June. The huge Antonov cargo aircraft that carried the Sentinel-2A from Germany, touched down at Cayenne airport in the early morning of 21 April. 26)

• April 8, 2015: The Sentinel-2A satellite is now being carefully packed away in a special container that will keep it safe during its journey to the launch site in French Guiana. The satellite will have one final test, a ‘leak test', in the container to ensure the propulsion system is tight. Bound for Europe's Spaceport in French Guiana, Sentinel-2A will leave Munich aboard an Antonov cargo plane on 20 April. Once unloaded and unpacked, it will spend the following weeks being prepared for liftoff on a Vega rocket. 27)

• February 24, 2015: Sentinel-2A is fully integrated at IABG's facilities in Ottobrunn, Germany before being packed up and shipped to French Guiana for a scheduled launch in June 2015. 28)

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Figure 10: Photo of the Sentinel-2A spacecraft in the thermal vacuum chamber testing at IAGB's facilities (image credit: ESA, IABG, 2015)

• In August 2014, Airbus Defence and Space delivered the Sentinel-2A environmental monitoring satellite for testing . In the coming months, the Sentinel-2A satellite will undergo a series of environmental tests at IABG, Ottobrunn, Germany, to determine its suitability for use in space. 29) 30)

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Figure 11: Sentinel-2A solar array deployment test at IABG (Airbus Defence & Space), image credit: ESA 31)

- Sentinel-2A is scheduled to launch in June 2015; Sentinel-2B, which is identical in design, is set to follow in March 2017. Together, these two satellites will be able to capture images of our planet's entire land surface in just five days in a systematic manner.

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Figure 12: Photo of the Sentinel-2A spacecraft at the satellite integration center in Friedrichshafen, Germany (image credit: Airbus DS, A. Ruttloff)

 

Launch: The Sentinel-2A spacecraft was launched on June 23, 2015 (1:51:58 UTC) on a Vega vehicle from Kourou. 32) 33)

RF communications: The payload data handling is based on a 2.4 Tbit solid state mass memory and the payload data downlink is performed at a data rate of 560 Mbit/s in X-band with 8 PSK modulation and an isoflux antenna, compliant with the spectrum bandwidth allocated by the ITU (international Telecommunication Union).

Command and control of the spacecraft (TT&C) is performed with omnidirectional S-band antenna coverage using a helix and a patch antenna. The TT&C S-band link provides 64 kbit/s in uplink (with authenticated/encrypted commands) and 2 Mbit/s in downlink..

The requirements call for 4 core X-band ground stations for full mission data recovery by the GMES PDS (Payload Data System).

In parallel to the RF communications, an optical LEO-GEO communications link using the LCT (Laser Communication Terminal) of Tesat-Spacecom (Backnang, Germany) will be provided on the Sentinel-2 spacecraft. The LCT is based on a heritage design (TerraSAR-X) with a transmit power of 2.2 W and a telescope of 135 mm aperture to meet the requirement of the larger link distance. The GEO LCT will be accommodated on AlphaSat of ESA/industry (launch 2012) and later on the EDRS (European Data Relay Satellite) system of ESA. The GEO relay consists of an optical 2.8 Gbit/s (1.8 Gbit/s user data) communication link from the LEO to the GEO satellite and of a 600 Mbit/s Ka-band communication link from the GEO satellite to the ground. 34)

To meet the user requirements of fast data delivery, DLR (German Aerospace Center) is funding the OCP (Optical Communication Payload), i.e. the LCT of Tesat, – a new capability to download large volumes of data from the Sentinel-2 and Sentinel-1 Earth observation satellites - via a data relay satellite directly to the ground. A contract to this effect was signed in October 2010 between ESA and DLR. 35)

Since the Ka-band downlink is the bottleneck for the whole GEO relay system, an optical ground station for a 5.625 Gbit/s LEO-to-ground and a 2.8 Gbit/s GEO-to-ground communication link is under development.

Orbit: Sun-synchronous orbit, altitude = 786 km, inclination = 98.5º, (14+3/10 revolutions/day) with 10:30 hours LTDN (Local Time at Descending Node). This local time has been selected as the best compromise between cloud cover minimization and sun illumination.

The orbit is fully consistent with SPOT and very close to the Landsat local time, allowing seamless combination of Sentinel-2 data with historical data from legacy missions to build long-term temporal series. The two Sentinel-2 satellites will be equally spaced (180º phasing) in the same orbital plane for a 5 day revisit cycle at the equator.

The Sentinel-2 satellites will systematically acquire observations over land and coastal areas from -56° to 84° latitude including islands larger 100 km2, EU islands, all other islands less than 20 km from the coastline, the whole Mediterranean Sea, all inland water bodies and closed seas. Over specific calibration sites, for example DOME-C in Antarctica, additional observations will be made. The two satellites will work on opposite sides of the orbit (Figure 13).

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Figure 13: Twin observation configuration of the Sentinel-2 spacecraft constellation (image credit: ESA)

 

Launch: The Sentinel-2B spacecraft was launched on March 7, 2017 (01:49:24UTC) on a Vega vehicle of Arianespace from Europe's Spaceport in Kourou, French Guiana. 36) 37) 38) 39)

• The first stage separated 1 min 55 seconds after liftoff, followed by the second stage and fairing at 3 min 39 seconds and 3 min 56 seconds, respectively, and the third stage at 6 min 32 seconds.

• After two more ignitions, Vega's upper stage delivered Sentinel-2B into the targeted Sun-synchronous orbit. The satellite separated from the stage 57 min 57 seconds into the flight.

• Telemetry links and attitude control were then established by controllers at ESOC in Darmstadt, Germany, allowing activation of Sentinel's systems to begin. The satellite's solar panel has already been deployed.

• After this first ‘launch and early orbit' phase, which typically lasts three days, controllers will begin checking and calibrating the instruments to commission the satellite. The mission is expected to begin operations in three to four months.

Sentinel-2B will join its sister satellite Sentinel-2A and the other Sentinels part of the Copernicus program, the most ambitious Earth observation program to date. Sentinel-2A and -2B will be supplying ‘color vision' for Copernicus and together they can cover all land surfaces once every five days thus optimizing global coverage and the data delivery for numerous applications. The data provided by these Sentinel-2 satellites is particularly suited for agricultural purposes, such as managing administration and precision farming.

With two satellites in orbit it will take only five days to produce an image of the entire Earth between the latitudes of 56º south and 84º north, thereby optimizing the global coverage zone and data transmission for numerous applications.

To ensure data continuity two further optical satellites, Sentinel-2C and -2D, are being constructed in the cleanrooms of Airbus and will be ready for launch as of 2020/2021.

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Figure 14: Illustration of the Sentinel-2B spacecraft in orbit (image credit: Airbus DS, Ref. 38)

Figure 15: This technical view of the Sentinel-2 satellite shows all the inner components that make up this state-of-the-art high-resolution multispectral mission (video credit: ESA/ATG medialab)

Figure 16: As well as imaging in high resolution and in different wavelengths, the key to assessing change in vegetation is to image the same place frequently. The Sentinel-2 mission is based on a constellation of two satellites orbiting 180° apart, which along with their 290 km-wide swaths, allows Earth's main land surfaces, large islands, inland and coastal waters to be covered every five days. This is a significant improvement on earlier missions in the probability of gaining a cloud-free look at a particular location, making it easier to monitor changes in plant health and growth (video credit: ESA/ATG medialab)

 


 

Mission status:

• April 19, 2019: The Copernicus Sentinel-2 mission takes us over one of the most remote islands in the world: Easter Island. Located in the Pacific Ocean, over 3500 km off the west coast of South America, this Chilean island is also known as Rapa Nui by its original inhabitants. The island was given its current name the day when the Dutch navigator Jacob Roggeveen arrived on 5 April 1722 – on Easter Sunday.

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Figure 17: Easter Island, with a size of 163.6 km2 and a population of 7500, is a Chilean island in the southeastern Pacific Ocean, at the south-easternmost point of the Polynesian Triangle in Oceania. A Sentinel-2 acquired this image on 7 April 2019, it is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO)

- The island is famous for its monolithic stone statues, called Moai, said to honor the memory of the inhabitants' ancestors. There are nearly 1000 scattered around the island, usually positioned near freshwater. Many are located near the Rano Raraku volcano, on the southeast coast. The white edges along the southern coast show the harsh waves colliding with the shore.

- An interesting feature of the image is the ochre-orange color of the Poike – the peninsula on the eastern end of the island. In ancient times, it is said that there was a lot of vegetation on the island. However, land clearing for cultivation and the Polynesian rat played a role in deforestation, leading to the erosion of the soil, particularly in the east.

- Several reforestation projects have been attempted, including a eucalyptus plantation in the middle of the island, visible in dark green. The brown patch to the right of the plantation is likely to be a burn scar from a wildfire.

- The majority of the island's inhabitants live in Hanga Roa, the main town and harbor on the west coast, clearly visible in the image. Interestingly, the long runway of the island's only airport was once designated as an emergency landing site for the US space shuttle.

- At the very edge of the southwest tip of the island lies Ranu Kao, the largest volcano on the island. Its shape is distinctive owing to its crater lake, one of the island's only three natural bodies of water.

- Many tourists are drawn to the island for its mysterious history and isolated position. What is relatively unknown is the existence of two small beaches on the northeast coast. Anakena beach has white, coral sand, while the smaller Ovahe beach, surrounded by cliffs, has pink sand.

• April 5, 2019: This week, ESA is focusing on its core Basic Activities, which, for Earth observation, include preserving precious data. Long-time series of datasets are needed to determine changes in our planet's climate so it is vital that satellite data and other Earth science data are preserved for future generations and are still accessible and usable after many years. This example includes a series of satellite images going back to 1998. 40) 41) 42)

Figure 18: This long-time series of over 150 images, captured by the US Landsat series and the Copernicus Sentinel-2 missions, shows the development over 21 years of an important land reclamation project in the Western Desert of Egypt. This comparison highlights how this agricultural project has developed between January 1998 and March 2019. These images are also featured on the Earth from Space video program (image credit: USGS/contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO)

- Egypt is over 95% desert, making a very small proportion of its land suitable for agriculture. As the demand for food grows, the need for agricultural development in desert areas has intensified.

- This set of images shows an important land reclamation project in East Oweinat, in the Western Desert of Egypt.

- The circular shapes in the images, each approximately 800 meters wide, indicate the irrigation method used here, with water being supplied by a set of sprinklers rotating around a central pivot. Fossil water, stored underground for thousands of years, comes from the Nubian Sandstone Aquifer, the largest known fossil aquifer discovered.

- The water in the East Oweinat area is low in salt content, making it ideal for cultivation purposes. Crops such as wheat, potatoes and barley are grown here, and are exported through the Sharq El Owainat airport, visible in the right side of the image.

- Another interesting feature in this time series is the drifting sand dunes visible mainly in the upper left corner, which is a phenomena common in sandy deserts with constant winds.

- Changes over the last 21 years are clearly visible when more fields develop, but the data also show other subtle changes within the fields themselves. This data can be used to monitor changes in land-cover over time. Long-term preservation of the satellite data from different missions ensures that changes to the land can be monitored by analyzing data from the archives.

• March 22, 2019: Today is World Water Day, but with millions of people in Mozambique, Malawi and Zimbabwe struggling to cope in the aftermath of Cyclone Idai, the notion of water shortages may not be at the forefront of our minds right now. Even so, floods, like we see here, lead to real problems accessing clean water. Whether the problem is inundation or water scarcity, satellites can help monitor this precious resource. 43)

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Figure 19: Water levels in the Theewaterskloof Dam in South Africa's Western Cape Province have dropped dramatically over recent years. The dam is the major source of water for domestic and agricultural uses in the region. Over the last year, this lack of water has caused the production of grain to drop by more than 36% and the production of wine grapes to drop by 20%, for example. It is estimated that it will need to receive at least three years of good winter rainfall for it to return to its earlier healthy level. Thanks to the TIGER initiative, the Stellenbosch University is applying machine-learning algorithms to data from the Copernicus Sentinel-1 and Sentinel-2 missions to carefully monitor the situation (video credit: ESA, the video contains modified Copernicus Sentinel data (2017–18), processed by ESA, CC BY-SA 3.0 IGO)

- With more than two billion people living without safe water and around four billion people suffering severe water scarcity for a least one month a year, achieving water for all is a huge challenge. And, coupled with a growing global population and climate change, it's likely to become even more challenging.

- Water allows life on Earth to thrive. The same water has existed for billions of years, cycling through the air, oceans, lakes, rocks, animals and plants and back again. The water we drink today may have once been inside a dinosaur!

- Our most precious resource is probably the strangest thing in the universe. Defying the laws of chemistry, it's the only known substance that can exist naturally as a gas, liquid and solid within a relatively small range of air temperatures and pressures found on the surface of Earth.

- Although there is no shortage of water on Earth, less than 3% is freshwater. Then the vast majority of this is locked up in icecaps and glaciers, leaving less than 1% available for drinking and other domestic needs, agriculture and industrial processes, and more.

- Freshwater is the single most important natural resource on the planet, but we are very rapidly running out of it – as illustrated by dwindling water bodies.

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Figure 20: The Earth's water cycle. The total amount of water present on the Earth is fixed and does not change. Powered by the Sun, water is continually being circulated between the oceans, the atmosphere and the land. This circulation and conservation of the Earth's water, known as the water cycle, is a crucial component of our weather and climate (image credit: ESA/AOES Medialab)

Figure 21: Glacial decline (10 December 2018). 44) A paper published recently in Nature Geosciences describes how a multitude of satellite images have been used to reveal that there has actually been a slowdown in the rate at which glaciers slide down the high mountains of Asia. This animation simply shows how glaciers in Sikkim in northeast India have changed between 2000 and 2018. One of the images is from the NASA/USGS Landsat-7 mission captured on 26 December 2000 and the other is from Europe's Copernicus Sentinel-2A satellite captured on 6 December 2018 [image credit: NASA/USGS/University of Edinburgh/ETH Zurich/ the image contains modified Copernicus Sentinel data (2018)]

• March 22, 2019: The 22 March is World Water Day, which focuses on the importance of freshwater. The Sustainable Development Goals of the United Nations aim to achieve a better and more sustainable future. Goal number 6 focuses on ensuring the availability and sustainable management of water for all by 2030. This image takes us over Lake Chad at the southern edge of the Sahara, where water supplies are dwindling. 45)

- Once one of Africa's largest lakes, Lake Chad has shrunk by around 90% since the 1960s. This receding water is down to a reduction of precipitation, induced by climate change, as well as development of modern irrigation systems for agriculture and the increasing human demand for freshwater.

Figure 22: This comparison shows Lake Chad imaged on 6 November 1984 by the US Landsat-5 satellite and on 31 October 2018 by the Copernicus Sentinel-2A satellite. The rapid decline of the lake's waters in just 34 years is clearly to see. These images are also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA (For Landsat image: USGS/ESA), CC BY-SA 3.0 IGO)

- Straddling the border of Chad, Niger, Cameroon and Nigeria, the lake is a major source of freshwater for millions of people in the area. It is also a source for irrigation, fishing and it was once rich in biodiversity.

- As the lake continues to dry up, many farmers and herders move towards greener areas or move to larger cities to seek alternative work. Several attempts have been made to replenish these shrinking waters, however little progress has been achieved.

- The borders of the lake's body are only partly visible in the most-recent image – as the majority of the shoreline is swamp and marsh. The Chari River, visible snaking its way towards Lake Chad at the bottom of the image, provides over 90% of the lake's waters. It flows from the Central African Republic following the Cameroon border from N'Djamena, where it joins with its main tributary the Logone River.

- The demand for water is growing inexorably. Access to water is vital – not only for drinking, but also for agriculture, energy and sanitation. By providing measurements of water quality and detecting changes, the Copernicus Sentinel-2 mission can support the sustainable management of water resources.

March 22, 2019: World Water Day! 46) The 66th United Nations General Assembly adopted a resolution declaring the Water Action Decade from 22 March 2018 to March 2028. The UN Water Action Decade is pursuing two goals:

- Spreading knowledge on the topic of water and water pollution control, including information on water-related Sustainable Development Goals (SDGs);

- more effective communication measures to implement water-related goals.

Figure 23: The UN Sustainable Goal 6 is crystal clear: Water for all by 2030. For World Water Day we take a look at ways that space can help this global challenge. While Earth-observing satellites monitor our precious water resources, technologies developed for human space missions also serve global needs in harsh environments here on Earth (video credit: ESA)

• March 21, 2019: The UN International Day of Forests is held annually on 21 March. It raises awareness of the importance of all types of forest and the vital role they play in some of the biggest challenges we face today, such as addressing climate change, eliminating hunger and keeping urban and rural communities sustainable. As the global population is expected to climb to 8.5 billion by 2030, forests are more important than ever. 47)

- This year, the International Day of Forests put a particular focus on education, but also on making cities a greener, healthier and happier place to live. In cities, trees can help many urban challenges. They act as air filters by removing pollutants, reduce noise pollution, offer shade and provide an oasis of calm in an otherwise busy urban environment, for example.

- While Bangkok, which is home to over eight million people, is an example of ongoing efforts being made to increase green spaces to improve city life, it also has a much-valued green haven, which can be seen in the center of the image.

- This horseshoe or lung-shaped, green oasis is Bang Kachao and is in the middle of the bustling city.

- Rich in gardens, mangroves and agricultural fields, the 2000 hectares of land is a significant contrast to the vastness of the city's urban sprawl. Fighting Bangkok's traffic and air pollution, Bang Kachao's lush green forest provides the dense city, and the surrounding Samutprakan province, with a flow of fresh air.

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Figure 24: Captured on 22 January 2019 by the Copernicus Sentinel-2B satellite, this true-color image shows Thailand's most populous city Bangkok, and its ‘Green Lung' Bang Kachao. The government-protected oasis of green is wrapped around the Chao Phraya River, which is seen flowing through the city of Bangkok before emptying into the Gulf of Thailand (image credit: ESA, the image contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO)

Legend to Figure 24: Bang Kachao is an artificial island formed by a bend in the Chao Phraya River and a canal at its western end. It lies south of the Thai capital Bangkok in the Phra Pradaeng District of Samut Prakan Province. The island, covering 16 km2, has been traditionally agricultural with only a relatively small population.

• March 21, 2019: Billions of image pixels recorded by the Copernicus Sentinel-2 mission have been used to generate a high-resolution map of land-cover dynamics across Earth's landmasses. This map also depicts the month of the peak of vegetation and gives new insight into land productivity. 48)

- Using three years' worth of optical data, the map can indicate the time of vegetation peak and variability of vegetation across seasons. Developed by GeoVille, an Austrian company specialized in the analysis of satellite data, this land-cover map dynamics map uses Copernicus Sentinel-2 archive data from 2015-18, and gives a complete picture of variations of vegetation. The map is displayed at a resolution of 20 m, however a 10 m version is available on request.

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Figure 25: Data from the Copernicus Sentinel-2 mission has been used to generate a new high-resolution map of vegetation across Earth's entire landmass. The new map depicts global vegetation dynamics and gives insight into land productivity. The time of vegetation peak i.e. the month at which greenness maximum occurs is shown in red (spring) and green (summer) to blue tones (autumn and winter.) The variability of vegetation greenness is represented by light tones in low amplitude areas such as managed grasslands, while high amplitudes are represented by saturated color tones. Areas with low biomass such as urban areas and open bodies of water are shown in black, while areas with higher biomass appear in grey and white tones (image credit: ESA, the image contains modified Copernicus Sentinel data (2016–18), processed by GeoVille)

- It can, for example, support experts working with land-cover classification and can serve as input for services in areas such as agriculture, forestry and land-degradation assessments.

- "In particular, we use this as a basis to develop services for the agrofood industry and farmers growing potatoes and other crops, as well as information on how vegetation changes over the year," explains Eva Haas, Head of GeoVille's Agricultural Unit (Innsbruck, Austria).

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Figure 26: The inland delta of the Niger River spreads across central Mali – a unique ecosystem in West Africa. A result of the Niger river flowing into the sandy Sahelian plains, this vast network of channels, swamps, and lakes mitigates the severity of the arid climate by supplying water during October and November (blue). In contrast the image shows the sparse rain fed vegetation in the surrounding region (dark green). This image is part of a new high-resolution map of vegetation across Earth's entire landmasses generated with Copernicus Sentinel-2 data (image credit: ESA, the image contains modified Copernicus Sentinel data (2016–18), processed by GeoVille)

- The land-cover dynamic layer was produced with GeoVille's processing engine LandMonitoring.Earth, a fully-automated land-monitoring system built on data streams from the Copernicus Sentinel-1 and Sentinel-2 missions, as well as ESA third party missions such as the US Landsat missions.

- "Using the system, we processed the complete Copernicus Sentinel-2 image archive along with artificial intelligence, machine learning and big data analytics," explains Michael Riffler, Head of Research and Development at GeoVille.

- "However, the key is the dense time-series of the Copernicus Sentinel-2 data which allows this information to be retrieved for the first time. To date, we have processed more than 23 billion pixels."

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Figure 27: The image shows different crop types around Emmelrod in the Netherlands. Here, green shows summer crops, red is potatoes, orange is market crops, yellow is cereals and blue depicts grassland. The area is important for the agrofood sector and, in particular, has strong ties to the international potato industry. By integrating Copernicus Sentinel-2 based crop-type monitoring directly into existing industry workflows, the agrofood industry can gain information about the growth and potential yield of crops, potatoes in particular, including the impact of ongoing droughts (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by GeoVille)

- The development has been done through ESA's Earth observation innovation hub – Φ-lab, and has been implemented by GeoVille and its subsidiary in the Netherlands – GEO4A.

- "This map forms an excellent foundation for other – more specialized – land cover classifications, whose development and deployment can be further accelerated by applying machine learning and AI," says Iarla Kilbane-Dawe, the head of ESA's Φ-Lab in Frascati, Italy.

- The LandMonitoring.Earth system is designed to efficiently implement major client solutions such as the European Copernicus Land Monitoring Service products. Experts can specify desired land monitoring data for any place on the globe for any given time period, and receive a quality-controlled output, depending on the required geographic coverage and frequency.

- The idea is to make information available to non-experts along with the specific resources and tools that they need.

• March 15, 2019: The Copernicus Sentinel-2 mission takes us over Nairobi, one of the fastest growing cities in East Africa. 49)

- The population of Nairobi has increased significantly in the last 30 years, with rural residents flocking to the city in search of employment. The city, visible in the center of the image, now has a population of over three million, with the vast majority spread over 200 informal settlements.

- Kibera, which can be seen as a light-colored patch at the south-western edge of the city, is considered one of the largest urban slums in Nairobi. Most residents live in small mud shacks with poor sanitation, a lack of electricity and limited access to clean water.

- While migration provides economic benefits to the city, it also creates environmental challenges. Owing to its urbanization, the city has spread into green spaces such as the nearby parks and forests. In this image, the densely populated area is contrasted with the flat plains of Nairobi National Park, directly south of the city. The 117 km2 of wide-open grass plains is colored in light-brown. The park is home to lions, leopards, cheetahs and has a black rhino sanctuary.

- The dark patches in the image are forests. The Ngong Forest, to the west of the city, includes exotic and indigenous trees, and hosts a variety of wild animals including wild pigs, porcupines, and dik-diks.

- To the north of the city, the dark Karura Forest is visible. The 1000 hectare urban forest features a 15 m waterfall, and hosts a variety of animals including bush pigs, bushbucks, suni and harvey's duiker, as well as some 200 bird species.

- Although Africa is responsible for less than 5% of global greenhouse-gas emissions, the majority of the continent is directly impacted by climate change. Rapid population growth and urbanization also exposes residents to climate risks.

- On 14 March 2019, the first regional edition of the One Planet Summit took place at the UN Compound, which is in the north of the city. The One Planet Summit, part of the UN Environment Assembly, focuses on protecting biodiversity, promoting renewable energies and fostering resilience and adaptation to climate change.

- Data from Copernicus Sentinel-2 can help monitor changes in urban expansion and land-cover change. Copernicus Sentinel-2 is a two-satellite mission. Each satellite carries a high-resolution camera that images Earth's surface in 13 spectral bands.

- As delegates gather in Nairobi for the UN Environment Assembly, ESA is saddened by the news of the Ethiopian Airlines accident. Lives lost included those working for organizations also dedicated to achieving a better world for all and who were travelling to the assembly. — Our thoughts are with the families, colleagues and friends of those affected.

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Figure 28: This image of the Sentinel-2 mission was captured on 3 February 2019, is also featured on the Earth from Space video program

• February 25, 2019: This Copernicus Sentinel-2 image of Figure29 shows a huge plume of sediment gushing into the sea following heavy rainfall in the Rome area. 50)

- The Tiber River can be seen snaking its way southwards in the image. The third longest river in Italy, it rises in the Apennine Mountains and flows around 400 km before flowing through the city of Rome and draining into the sea near the town of Ostia. The Tiber River plays an important role in sediment transport, so coastal waters here are often discolored. However, the recent rains resulted in a large amount of sediment pouring into the Tyrrhenian Sea, as this image shows. The sediment plume can be seen stretching 28 km from the coast, carried northwest by currents.

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Figure 29: The Copernicus Sentinel-2B satellite captured this true-color image on 5 February 2019, just three days after heavy rainfall in Rome and the surrounding area of Lazio, Italy. It shows sediment gushing into the Tyrrhenian Sea, part of the Mediterranean Sea. The downpour on 2 February led to flooded streets, the closing of the banks of the Tiber River and several roads (image credit: ESA, the image contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO)

• February 22, 2019: The Copernicus Sentinel-2A satellite takes us over western Sicily and the islands of Favignana and Levanzo in Italy. The image of Figure 30 shows a false-color image included the near-infrared channel and was processed in a way, that makes vegetation appear in bright red. 51)

- The bright turquoise colors, near the port city of Trapani, at the top of the image, and the Isola Grande in the middle of the image, depict salt marshes. Both the Saline di Trapani e Paceco Nature Reserve and the Stagnone Nature Reserve with their shallow sea waters, windy coast and abundant sunshine, make the area between Marsala, at the bottom of the image, and Trapani an ideal place for salt production.

- The reserve consists of more than 1000 hectares of landscape dotted with windmills, migratory birds such as flamingos and light-red lagoons visible in summer. This greenish-blue color is heavily contrasted with the black of the open Mediterranean Sea.

- The islands, off the coast, are rich in history, both boasting Paleolithic and Neolithic cave paintings. The most famous being the Grotta del Genovese on the picturesque island of Levanzo, at the top left of the image. The cave was discovered only in 1949 and is estimated to be between 6000 and 10 000 years old.

- Below, the butterfly-shaped island of Favignana, known for its tuna fisheries and a type of limestone known as tufa rock, is the largest of the Aegadian islands. In 241 BC, one of the Punic Wars' naval battles was fought at the Cala Rossa (Red Cove), named after the bloodshed.

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Figure 30: Captured on 3 September 2018 by the Copernicus Sentinel-2A satellite, this false-color image shows part of western Sicily in Italy and two of the main Aegadian Islands: Favignana and Levanzo. This image is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• February 15, 2019: Copernicus Sentinel-2 brings you some of the jewels of the Maldives for Valentine's week. Arguably one of the most romantic destinations in the world, the Maldives lie in the Indian Ocean about 700 km southwest of Sri Lanka. The nation is made up of more than 1000 coral islands spread across more than 20 ring-shaped atolls. 52)

- Like many low-lying islands, the Maldives are particularly vulnerable to sea-level rise. In fact, the Maldives are reported to be the flattest country on Earth, with no ground higher than 3 m and 80% of the land lying below 1 m. With satellite records showing that over the past five years, the global ocean has risen, on average, 4.8 mm a year, rising seas are a real threat to these island jewels.

- With the promise of white sandy beaches, azure ocean waters and coral reefs, this romantic getaway draws more than 600,000 tourists every year. While tourism is extremely important for the national economy, development on these pristine islands create pressures, such as ensuring an adequate supply of freshwater, treating sewage and potential pollution entering the ocean. Other environmental issues facing the Maldives include the loss of habitats of endangered species and the damage to the coral reefs.

- The Maldives are undoubtedly fragile but one of the most beautiful places on the planet, and a place to be loved and cherished now and in the future. Valentine's Day reminds us of love and maybe this year and beyond it's good to remember to love our planet.

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Figure 31: A number of these little islands can be seen in the image, with the turquoise colors depicting clear shallow waters dotted by coral reefs and the red colors highlighting vegetation on land. Different cloud formations can also be seen, the difference in appearance is likely to be due to the different height above the surface. This image, which was captured on 26 August 2015, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2015), processed by ESA, CC BY-SA 3.0 IGO)

• February 08, 2019: Captured on 1 October 2018 by the Copernicus Sentinel-2A satellite, the image of Figure 32 features part of northeast Kenya – an area east of the East African Rift Valley. 53)

- The region tends to be very arid and this false-color image has been processed to highlight different types of rock, soil and sand in pinks, purples and yellows.

- Part of the ‘great north road' can also been seen running from the bottom-left to the top-right. The road is one of the best in the country, linking Nairobi in the south of the country to Ethiopia. The northern 500-km stretch from Isiolo to the Kenyan–Ethiopian border town of Moyale took about nine years to build and was completed recently, but has reduced travel time from Nairobi to Moyale from three days to about 12 hours and opened up new opportunities for trade and business. Moyale can be seen in the top-right of the image.

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Figure 32: The bright green at the top of the image depicts vegetation, but the rest of the area appears relatively devoid of vegetation. Several dry river beds can also be seen etched into the landscape and the black shape in the middle-left appears to be an area of freshly burnt land. The lack of water has, at times, led to clashes between clans over access to water and pasture for cattle. When the rains do come, however, this dry dusty land can burst into life and turn a rich green. This Copernicus Sentinel-2A image is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• February 04, 2019: Wildfires can cause devastation and are also to blame for more than a quarter of greenhouse gases being released into the atmosphere. Satellites play a key role in mapping landscape scarred by fire – but the Copernicus Sentinel-2 mission has revealed that there are more fires than previously thought. 54)

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Figure 33: This Copernicus Sentinel-2 image from 26 January 2019 shows fire-scarred land near the Betty's Bay area of Cape Town in South Africa. This false-color image has been processed to show burned areas in dark greys and browns, and areas covered with vegetation are shown in red [image credit: ESA, the image contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO] 55)

- From the vantage of space, satellites can be used to detect fires and monitor how they spread and, in the first instance, this can often help relief efforts. However, satellites are also important for mapping the scars that fires leave in their wake, particularly in remote regions.

- It is currently estimated that fires contribute 25–35% of total annual greenhouse gas emissions to the atmosphere so more precise information gained from satellite-based scar-burn maps could help to better understand how they add to the greenhouse effect.

- Land disturbed by fire is an ‘essential climate variable', which are global datasets for the key components of Earth's climate.

- Fire-scar mapping is also used for managing natural resources, assessing fire risk and for adopting mitigating strategies, for example.

- Thanks to Copernicus Sentinel-2's ability to zoom in on our planet, researchers have discovered that there are more areas that are being affected by fire than previously thought.

- A paper published recently in Remote Sensing of the Environment describes how researcher used the high-resolution imaging capability of the Copernicus Sentinel-2 mission to produce the first detailed continental map of burns caused by wildfires. 56)

- Sentinel-2 is a two-satellite constellation built for the EU's Copernicus environmental monitoring program. Each identical satellite carries a high-resolution multispectral imager. The mission has a myriad of uses, particularly related to monitoring the health of world's vegetation and mapping how the surface of our land changes.

- The authors focussed on sub-Saharan Africa as the region that accounts for around 70% of burned area worldwide according to global satellite databases, making it the ideal testbed for evaluating the potential for improving the understanding of global impacts of fire.

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Figure 34: Copernicus Sentinel-2 reveals more fires in Africa than thought. The authors of Ref. 56) focussed on sub-Saharan Africa and found that 4.9 million km2 of land had been burned in 2016 (left image), which is 80% more than reported with information from coarser-resolution satellite sensors (right image). These new-found areas comprised mainly burned areas smaller than 100 ha (image credit: ESA, the image contains modified Copernicus Sentinel data (2016), processed by the University of the Basque Country–E. Roteta)

• January 25, 2019: Zaragoza is the capital of the province of Zaragoza in the region of Aragon in northeast Spain. It is home to about half of Aragon's population, making it the fifth largest municipality in Spain. 57)

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Figure 35: This Copernicus Sentinel-2B image features the city of Zaragoza nestling in the Ebro valley and flanked by mountains to the south. The image was captured on 25 February 2018, it is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

- In the top-right of the image, the Ebro River can be seen winding its way through the city. Between its source in the Cantabrian Mountains in the northwest and its delta on the Mediterranean coast, the Ebro River is fed by more than 200 tributaries as it flows across much of northern Spain. In fact, the Ebro River discharges more water into the sea than any other river in Spain.

- In an otherwise arid region, the river is used to irrigate crops in the valley – fields can be seen in the top-right of the image.

- To the south of the city and dominating the image, lie mountains, relatively devoid of vegetation. There are also mountains to the north that are beyond the frame of this image. These mountains, which effectively surround Zaragoza, form a barrier to moisture from the Atlantic Ocean and from the Mediterranean Sea, creating a semi-arid climate.

- On average, Zaragoza only has about 350 mm of precipitation a year, compared to Paris in France, for example, which has around 650 mm of precipitation a year. In recent years, efforts – from discounts on water-saving products to new watering systems for parks – have been in helping to reduce water consumption. Efforts such as these resulted in Zaragoza's per capita use of water dropping from 150 liters/day in 1997 to just 99 liters/day by 2012.

• January 18, 2019: The Copernicus Sentinel-2 mission takes us over Gangotri, one of the largest glaciers in the Himalayas and one of the main sources of water for the Ganges River. 58)

- The Gangotri Glacier is in the Indian Himalayan state of Uttarakhand. The head of the glacier can be seen in the lower-right of the image near the Chaukhamba Peak. From here, Gangotri flows around 30 km northwest, but like many of the world's glaciers it is in retreat. Studies suggest that Gangotri has been receding for well over 200 years. Measurements have shown, that it retreated by as much as 35 meters a year between the mid-1950s and mid-1970s. While this has now reduced to about 10 meters a year, observations show that the glacier is thinning.

- The glacier's terminus is called Gomukh, which means ‘mouth of a cow', presumed to describe what the snout of this huge glacier once resembled. Importantly, the headwaters of the Bhagirathi River form here. In Hindu culture and mythology, this is considered to be the source of the Ganges River and consequentially the destination for many spiritual pilgrimages and treks. Gomukh is a 20 km trek from the village of Gangotri, which is in the top left of the image of Figure 36. While Gomukh and Gangotri have much spiritual significance, the Bhagirathi River offers an important supply of freshwater as well as power as it passes through a number of power stations, including the Tehri hydroelectric complex 200 km downstream (not pictured).

- Gangotri is in an area also known as ‘the third pole', which encompasses the Himalaya-Hindu Kush mountain range and the Tibetan Plateau. The high-altitude ice fields in this region contain the largest reserve of freshwater outside the polar regions. With such a large portion of the world's population dependent on water from these cold heights, changes in the size and flow of these glaciers can bring serious consequences for society by affecting the amount of water arriving downstream.

- From the vantage point of space, satellites, such as the Copernicus Sentinels, provide essential information to monitor the changing face of Earth's glaciers, which are typically in remote regions and therefore difficult to monitor systematically from the ground.

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Figure 36: Sentinel-2 captured this image on 7 January 2018, it is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• January 11, 2019: The Copernicus Sentinel-2B satellite takes us along the lower reaches of the brown, sediment-rich Uruguay River. Here, the river forms the border between Argentina and Uruguay and is the site of the Esteros de Farrapos e Islas del Río Uruguay wetlands. 59)

- Composed of lagoons, swamps and 24 islets, the Esteros are a haven for wildlife, protected as a national park and included on the List of Wetlands of International Importance of the Ramsar Convention.

- This wetland system is home to 130 species of fish, 14 species of amphibian, 104 species of bird – a quarter of all birds found in Uruguay – and 15 species of mammal, including the maned wolf, the largest canid (meaning dog-like) species in South America.

- A tourist attraction and a waterway for transport, the Esteros also play an important role in regulating flood levels and maintaining water quality, as well as safeguarding the banks of the Uruguay River from erosion.

- Visible to the lower left – its built structures shown in grey-white – is the Argentinian town of Gualeguaychú. On the eastern shore of the Uruguay River is the Uruguayan city of Fray Bentos, an important national harbor, famous for a plant that once exported corned beef around the world. Now inactive, this sprawling industrial complex has become a World Heritage Site.

- The dark green area to the east of the Esteros is devoted to forestry, an important industry for the region. A pulp mill is located close to Fray Bentos.

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Figure 37: Sentinel-2B acquired this image of the Uruguay River wetlands on 17 August 2018, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• December 21, 2018: The Copernicus Sentinel-2 mission takes us over the island of South Georgia. Linked with the South Sandwich Islands to form a British Overseas Territory, this southern Atlantic island is a haven for a vast array of wildlife. 60)

- As part of the South Georgia and the South Sandwich Islands – a British overseas territory – this island is the largest in the territory covering 3500 km2. South Georgia is 167 km long and 1.4 to 37 km wide (coordinates: 54.4°S 36.7°W). Its mountainous terrain has numerous high peaks over 2000 m with the highest, Mount Paget, standing over 2930 m.

- Around five million seals call the islands home, as well as 65 million birds of 30 different species. Migrating whales and various fish species populate the surrounding waters and there is a large penguin population.

- First discovered by Captain James Cook in 1775, there is no permanent human population on the island, due to its remote location and inhospitable environment. Nevertheless, a BAS (British Antarctic Survey) research station operates in the capital, King Edward Point, in the island's center. This is a center for applied fisheries research, while on Bird Island, lying off the north-west tip of South Georgia, scientists and support staff focus on research into bird and seal biology.

- As we can see clearly in the image, South Georgia is mostly covered in snow. Its polar climate gives it short and very cold summers, and long, freezing and overcast winters. The rugged landscapes of the island are often said to leave visitors in awe, with two mountain ranges dominating - the Allardyce towards the middle of the island and Salvesen in the south.

- In 2012 the UK Government designated South Georgia as one of the world's largest sustainable use Marine Protected Areas. Significant investment has also been made in fisheries management and scientific research, as well as targeted conservation efforts to help protect the albatross. South Georgia is home to the Wandering Albatross – the largest flying bird species in the world.

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Figure 38: This image of Sentinel-2, which was captured on 22 February 2018, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• December 7, 2018: The Copernicus Sentinel-2 mission takes us over the Chachani mountain in Peru. Standing at over 6000 m, Chachani is the tallest of the mountains near the Peruvian city of Arequipa. The outskirts of the city and part of the airport runway are just visible in the center bottom of the image. The city is home to around 900,000 people and is renowned for its dramatic cityscape, surrounded by three volcanoes. Chachani is shown in the center of the image of Figure 39. 61)

- Arequipa is also known as la Ciudad Blanca or the White City thanks to the prevalence of baroque buildings carved from white volcanic sillar stone in its center. The volcanoes, overlooking the city, naturally form an important part of the city's identity.

- Heavy shades of red, showing vegetated areas, dominate this false-color image. The varying tones represent different vegetation types, at different stages in the annual vegetation cycle. The near-infrared channel of Copernicus Sentinel-2 has been used to achieve this false-color effect. A number of crops are grown in this area, including maize, asparagus and hot peppers (rocotos), which feature in many local dishes, such as the region's signature dish of rocoto relleno.

- In the center-right of the image we can see a body of water called Aguada Blanca. This is part of a protected natural area, covering 360,000 hectares. Llamas and alpacas live here, as well as flamingos which have made the surrounding lagoons and wetlands of the Andean plains their home. Wool trade is a huge industry for the region, with artisan crafts also booming in recent years.

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Figure 39: This image of the Peruvian mountain scene was captured on 14 July 2017 on Sentinel-2 near the city of Arequipa; it is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• November 16, 2018: The Copernicus Sentinel-2A satellite takes us over the island of Fogo, Cabo Verde. This small volcanic island, which can be seen in the right of the image, is about 25 km in diameter and home to around 35,000 people. The combined population of the nine inhabited islands that make up the Republic of Cabo Verde is estimated to be 550,000. These islands lie in the Atlantic Ocean, around 600 km off the west coast of Africa. 62)

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Figure 40: The Sentinel-2 satellite captured this image of the Cape Verde island group on 22 January 2018, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA , CC BY-SA 3.0 IGO)

- The black area in the island's center is the crater of the Pico do Fogo – Fogo's highest point stands at 2800 m, and is also the highest peak in the entire Republic of Cabo Verde. It last erupted in November 2014 to February 2015, totalling 77 days of activity. In some places, up to 75% of the buildings were destroyed, mostly by lava.

- In the northeast of the island, vibrant green highlights a vegetated area, where coffee is grown. There is a long tradition of coffee growing here, although the semi-arid climate and reduced rainfall in recent years make this a challenge. Other crops grown on the island include peanuts, oranges, tobacco, and beans. More arid and rocky areas are shown in a mix of yellow and orange.

- In the bottom left of the image we can see the island of Brava, with three islets above: Rombos–Grande, Luís Carneiro, and Cima.

- Historically, the name "Cape Verde" has been used in English for the archipelago and, since independence in 1975, for the country. In 2013, the Cape Verdean government determined that the Portuguese designation Cabo Verde would henceforth be used for official purposes, such as at the United Nations, even in English contexts. Cape Verde is a member of the African Union.

• November 02, 2018: The Copernicus Sentinel-2B satellite takes us over Semarang, Indonesia. A port city on the north coast of Java, Semarang is the fifth-largest city in the country, covering some 374 km2 and home to just over 1.5 million people. 63)

- This true-color image of Figure 41 shows the heart of the bustling regional commercial center in the bottom-left, where a range of industries from fishing to glass manufacture and textiles operate. Exports of rubber, coffee, shrimp, tobacco, and cacao, among other products, pass through the city's harbor, which can also be seen in the bottom-left of the image.

- The Java Sea dominates the left part of the image. Flood management remains an ongoing challenge for the area, with the city being prone to tidal flooding.

- The island nation of Indonesia is particularly vulnerable to sea-level rise. Some parts of Semarang, such as the residential area of Candi Baru, shown in the bottom-left of the image, stand just above sea level.

- In the right of the image we can see mainly agricultural land, with rice fields stretching across the landscape. Land subsidence has been widely reported in the area, particularly in the northern part of Semarang, accelerated by population increases and urban development.

- The impacts of subsidence include the wider expansion of (coastal) flooding areas, cracking of buildings and infrastructure, and increased inland seawater intrusion.

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Figure 41: This image, which was captured on 9 May 2018, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• October 26, 2018: The Copernicus Sentinel-2B satellite takes us over Kyoto, shown in the top right, and Osaka, seen in the bottom left of this image. This striking false-color image captures two of Japan's larger cities, which are home to 1.5 and 2.7 million people, respectively. Both are, of course, significantly smaller than the capital. Greater Tokyo has a population of around 38 million, making it the largest megacity in the world. 64)

- The landscape of the Kyoto Prefecture varies from mountains and bamboo groves to waterfalls and forests. Vegetation is shown in vibrant shades of blue here, with built-up areas represented in yellow-red tones. Longer wavelength bands have been used when processing the image to make it easier to differentiate land cover, penetrate haze, and identify bodies of water.

- While almost three-quarters of the country is mountainous, less than 10% is covered by bodies of water. Northeast of Kyoto, we can see Lake Biwa, located in the neighboring Shiga Prefecture. This is the largest freshwater lake in Japan, covering an area of 672 km2.

- The area is famous for being home to Narezushi, the precursor to modern-day sushi. The dish is thought to have originated in southeast Asia around the second century CE (Common Era). People began to prepare it in Japan between 8 and 10 CE. Funazushi, using nigorobuna fish, typical of the Lake area, is prepared by fermenting and preserving the fish with rice and salt in barrels for up to a year. The result is a strong-tasting dish, often compared to blue cheese and accompanied by sake.

Visitors from all over the world travel to Kyoto, which is widely regarded as the cultural capital of the country. They are drawn by sites such as the Fushimi Inari Shrine, a UNESCO world heritage site, where more than 10,000 Torii gates stand in dedication to the Shinto god of rice.

- The multicultural food scene of Osaka, meanwhile, attracts foodies, on the lookout for tasty street food and an insight into "kappo dining." Meaning ‘to cut and to cook', this less formal cuisine focuses on bringing the diner and the chef together, with diners often given the chance to chat with the person who is preparing their meal.

- Over 100 Member governments and 120 participating organizations will gather in Kyoto from 29 October – 2 November for the Group on Earth Observations (GEO) Week 2018. The week's events will focus on the use of Earth observation for the benefit of humankind through GEO's three priority areas: the Sendai Framework for Disaster Risk Reduction, the Paris Climate Agreement, and the UN Sustainable Development Goals.

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Figure 42: This image, which was captured by Sentinel-2 on 11 May 2018, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• October 22, 2018: As part of a scientific collaboration with the Mexican Space Agency, AEM (Agencia Espacial Mexicana) and other Mexican scientific public entities, ESA has combined images from the Copernicus Sentinel-2 mission to produce a detailed view of the different types of vegetation growing across the entire country. 65)

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Figure 43: The high-resolution land-cover map combines images captured by Copernicus Sentinel-2 between 2016 and 2018. The original map, generated with 10 m resolution imagery, is available via the Climate Change Initiative's Land Cover 10 m viewer (image credit: ESA, the image contains modified Copernicus Sentinel data (2016–18) processed by ESA–CCI Land Cover Project/UC Louvain/Brockmann Consult)

- Sentinel-2 is a two-satellite constellation built for the EU's Copernicus environmental monitoring program. Each identical satellite carries a multispectral imager that can distinguish different types of vegetation and crops. It can also be used to determine numerous plant indices such as the amount of chlorophyll and water in leaves to monitor changes in plant health and growth.

- The mission has a myriad of uses, one of which is to provide information to map land cover so that changes in the way land is being used can be monitored.

- Thanks to this Copernicus mission and to ESA's Climate Change Initiative Land Cover project, Mexico's land cover has been mapped at a resolution of 10 m. Land-cover mapping breaks down the different types of material on Earth's surface, such as water bodies, different forms of agriculture, forests, grasslands and artificial surfaces. This information is important for understanding changes in land use, modelling climate change, conserving biodiversity and managing natural resources.

- This is a valuable source for scientific studies and practical applications alike. Daniela Jurado from Mexico's National Commission for the Knowledge and Use of Biodiversity said, "Having access to such a detailed map is not only useful for scientific research such as understanding fluxes associated with the carbon cycle, but also for managing our natural resources and for conserving biodiversity. - It is also important for land-use management and for monitoring urban expansion."

- Alejandra Aurelia López Caloca, from the Center for Research in Geospatial Information Sciences added, "Indeed, this new map reveals a lot about our country. It is very helpful for studying the growth of cities and how rural areas are transitioned into urban environments. In addition, it is going to be a real help to understand where bodies of water are highly dependent on precipitation and to pinpoint those areas that are at risk of flooding. The new map allows us to identify the status land cover, specifically the agricultural kind so this will really help us understand how our land is being farmed."

- ESA has been coordinating global land cover maps since 2002 through its GlobCover and Climate Change Initiative Land Cover projects at a resolution of 300 m. But with the Copernicus Sentinel-2 pair now in orbit, land cover can be mapped at a resolution of 10 m.

- In the same vein, a land-cover map of Central America is also now available (Figure 44).

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Figure 44: Central America land cover. ESA has combined images from the Copernicus Sentinel-2 mission to produce a detailed view of the different types of vegetation growing across Central America. The high-resolution land-cover map combines images captured by Copernicus Sentinel-2 between 2016 and 2018. The original map, generated with 10 m resolution imagery, is available via the Climate Change Initiative's Land Cover 10 m viewer (image credit: ESA, the image contains modified Copernicus Sentinel data (2016–18) processed by ESA–CCI Land Cover Project/UC Louvain/Brockmann Consult)

• October 19, 2018: The Copernicus Sentinel-2A satellite takes us over Lake Disappointment in northwest Australia. Found in one of the most remote areas of the country, it is believed to have been discovered by an early explorer called Frank Hann in 1897. He was convinced that the series of creeks that he had been following in the east Pilbara area would lead to a freshwater lake and drinking water supply. Such was his disappointment to find a salt lake at the end of his journey, he gave the lake its memorable name. 66)

- Although the lake is dry most of the time, it is home to many species of water birds. When it is full, primarily during very wet periods, the lake retains water and allows no outflow and is hence classified as an endorheic basin.

- In this false-color image of Figure 45, the differences in the shades of blue in the lake reflect the depth of the water. The darker the blue, the deeper the water is. A higher concentration of salt might also explain the different colors of the water round the edges of the lake.

- It is likely that the red lines spread across the top part of the image represent some form of vegetation in this predominantly arid area on the edge of the Gibson Desert. Karlamilyi National Park, Western Australia's largest and most remote national park, can be found north of the lake. The park spans over 1.3 million hectares between the Great Sandy Desert and the Little Sandy Desert.

- Covering an area of almost 380,000 km2, the Shire of East Pilbara, also to the north of the lake, is the third largest municipality in the world. The population was registered as only around 11,000 in 2017, with mining constituting the backbone of the local economy.

- The Sentinel-2 mission for Europe's Copernicus program is tasked with monitoring our changing lands. Designed specifically to monitor vegetation, it can also detect differences in sparsely vegetated areas, as well as the mineral composition of soil.

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Figure 45: Lake Disappointment in northwest Australia. This image, which was captured on 1 April 2017, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• October 12, 2018: The Copernicus Sentinel-2B satellite takes us over South Sudan (Figure 46). Having gained independence from Sudan in July 2011, South Sudan is the youngest country in the world. It has an estimated population of 13 million people, more than 80% of whom live in rural areas. Most of the population relies on farming, fishing or herding to meet their food and income needs. 67)

- The Sobat river is traced in a vibrant green color along the left part of the image. This is the most southerly of the great eastern tributaries of the White Nile, the section of the Nile between Malakal, South Sudan and Khartoum, Sudan.

- Tropical forests, swamps and grassland make up the majority of South Sudan's terrain. A large, swampy area called the Sudd, which is about 320 km wide and 400 km long, can be found in the center of the country. This is thought to be one of the largest freshwater ecosystems in the world and is fed by the White Nile and rainfall runoff from surrounding areas. It is home to large fish populations, millions of migratory birds, and various endangered species.

- The area has also provided shelter for refugees fleeing the ongoing Sudanese civil war, which broke out in South Sudan in December 2013.

- The red and gold in the lower-central part of the image shows smoke from a fire. The smoke is being driven by a northerly wind. The black parts of the image, similarly, show burnt areas of land – possibly the result of slash and burn agriculture. By burning dry grass, herders are able to fertilize the soil with ash, promoting new growth that can be used to feed livestock. Subsistence farmers also tend to use this method to manage land, returning nutrients to the soil and clearing the ground of unwanted plants in the process. Some of the negative longer-term impacts of this practice include air pollution, deforestation and erosion.

- The Sentinel-2 satellites carry an innovative wide swath high-resolution MSI (Multispectral Imager) for observing the land and vegetation. The mission mainly provides information for agricultural and forestry practices and for helping manage food security.

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Figure 46: This image of South Sudan, which was captured on 18 January 2018 with MSI on Sentinel-2B, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• October 5, 2018: A 7.5-magnitude earthquake and tsunami hit Indonesia on 28 September, destroying homes and hundreds of lives. As the death toll continues to rise, the effects of this natural disaster are far-reaching, with hundreds of thousands of people seeking access to food, water and shelter in the aftermath of this tragedy. 68)

Figure 47: Fault line land movement in Indonesia. This animation, derived from Copernicus Sentinel-2 data, shows land movement along the fault line at Palu, Indonesia. The earthquake and subsequent tsunami have destroyed homes and are thought to have claimed at least 1400 lives according to the most recent reports. It has been estimated that up to 1.5 million people will be affected by these events (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

- Satellite data can be used to support international disaster risk management efforts, such as those in Indonesia. One of the ways in which ESA is contributing to this area is through leading a range of activities in the framework of the Committee on Earth Observation Satellites (CEOS) Working Group on Disasters.

- In particular, the Geohazards Office, led by the French Geological Survey (BRGM) liaises with practitioners on the exploitation of Earth observation processing services to support hazard mapping and risk assessment. This is in the spirit of the International Forum on Satellite Earth Observation and Geohazards.

- BRGM experts have generated displacement maps using Copernicus Sentinel-2 acquisitions from 17 September and 2 October.

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Figure 48: Thematic experts from the Corinth Rift Laboratory in Greece have generated a displacement map using Copernicus Sentinel-2 acquisitions from 17 September and 2 October, showing the impact of the 7.5-magnitude earthquake that hit Indonesia on 28 September 2018. The use of the Cloud processing platform GEP demonstrates the ability to rapidly provide automated measurements (image credit: ESA, the map contains modified Copernicus Sentinel data (2018), processed by the Corinth Rift Laboratory)

- Thematic experts from the Corinth Rift Laboratory in Greece have generated similar results using the Cloud processing platform GEP, which has been designed to rapidly provide automated measurements.

- As shown in the images, the earthquake triggered deformations of several meters and a tsunami. Around 1400 people are reported to have lost their lives, hundreds have been hospitalized and many more thousands are thought to have been displaced. It has been estimated that up to 1.5 million people will be affected by these events.

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Figure 49: Indonesia earthquake displacement data [image credit: ESA, the map contains modified Copernicus Sentinel data (2018), processed by the French Geological Survey (BRGM)]

• September 25, 2018: The drought that swept through Europe this year has hit European farmers hard. Sustained high temperatures and the lack of rain have badly affected the agrofood industry, including the important potato sector. - Europe has the highest level of potato consumption in the world at almost 90 kg per capita per year, and is the second largest potato producer globally with some 53 million tons harvested annually. 69)

- The price of potatoes varies from year to year, but this important crop has now reached the highest value seen in recent years on the commodity futures exchange. All of this, of course, means that the French fries, so well-loved in Europe, are about to get more expensive.

Figure 50: Drought in the Netherlands. This animation shows the differences in vegetation development detected by the Copernicus Sentinel-2 satellites in the Emmeloord region of the Netherlands between August 2017 and August 2018. The effects of the drought are clear here with a significant shift from lush greens in 2017 to brown shades the following year clearly visible. As well as providing detailed information about Earth's vegetation, Sentinel-2 is designed to play a key role in mapping differences in land cover to understand the landscape, map how it is used and monitor changes over time (image credit: ESA, the image contains modified Copernicus sentinel data (2018), processed by ESA/GeoVille)

- It is not all doom and gloom though. Earth observation data, including Copernicus Sentinel-1 and Sentinel-2 satellites as well as very high resolution data from other missions, can be used to help mitigate a number of challenges faced by the industry, from storage to disease monitoring, while increasing logistics and trading efficiencies.

Figure 51: The drought that swept through Europe this year has hit European farmers hard. Sustained high temperatures and the lack of rain have badly affected the agrofood industry, including the important potato sector. This animation shows early season crop type classification in the Emmeloord region of the Netherlands in June 2018 based on Copernicus Sentinel-2 data. Green shows summer crops, red: potatoes, orange: vegetables and flowers, yellow: cereals, and blue: grass (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA/GeoVille)

- A new service will help reduce the effect of these problems using satellite data. The agrofood industry and farmers growing potatoes and other crops should soon save money, get better prices and help protect their crops from disease using satellite data collected that will be sent directly to them through ESA's novel EOPLUG-IN service.

- The service will help with storage, trading and disease monitoring. This will help growers conserve potatoes better and longer, assist trading decisions, and improve the detection of certain diseases to reduce losses.

- EOPLUG-IN, recently launched through ESA's new Earth observation innovation hub – the Φ-lab, will enable fast, easy access to continuous business intelligence data streams for industry via machine-based technologies.

- This system will provide the means to integrate satellite data and other information streams directly in existing industry workflows in a business-friendly format. This will inform the agrofood industry, for example, about the impact of ongoing droughts, crop failures and diseases, helping users to save money, get better prices, and as a result, also help make potatoes cheaper for European consumers.

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Figure 52: EOPLUG-IN launch. Amanda Regan (center left), head of ESA's Φ-lab invest office, kicks off Earth Observation PLUG-IN with GeoVille's commercial director Andreas Walli (center right), project manager Eva Haas (right), and software engineer Philip Krauss (left), image credit: ESA

Legend to Figure 52: EO PLUG-IN, launched through ESA's new innovation hub – the Φ-lab, is funded by the InCubed scheme and will enable easy, fast access to continuous business intelligence data streams for industry via machine -based technologies. This system will provide the means to integrate Earth observation data and other information streams directly within existing industry workflows in a business-friendly format. This will inform the agrofood industry, for example, about the impact of ongoing droughts, crop failures and diseases, helping users to save money, get better prices, and as a result, also support European consumers.

- Janny Peltjes, the managing director of HLB BV, a member of the Dutch agrofood cluster, expects that "the novel satellite-based system will be able to spatially detect crop diseases, thereby providing means to efficiently target affected areas, saving pesticide application and safeguarding production".

- As the system is scalable, the services can be expanded to different topics and sectors. Agriculture is a low margin industry and increasing margins on the 53 million tons of potatoes produced in Europe each year will save millions for this €7 billion industry.

- The service is developed by GeoVille Information Systems and Data Processing GmbH, the Austrian Earth Observation Data Center, and Dutch partners from the agriculture and food industries including Hermess and HLB.

- EOPLUG-IN is the first ESA InCubed activity. It integrates Big Data, combining non-Earth observation and Earth observation data using artificial intelligence, adopting a value chain approach, including reputable companies, and trailing the service with the agrofood cluster as a baseline for global roll out.

• September 21, 2018: The Copernicus Sentinel-2A satellite takes us over the largest island of the Azores: São Miguel. Resting at the intersection of the Eurasian, African and North American tectonic plates, the Azores form a string of volcanic islands in the North Atlantic Ocean, some 1500 km west of mainland Portugal. The nine major islands are divided into three groups, with São Miguel falling into the eastern group. 70)

- The archipelago is an autonomous region of Portugal and home to just under 250,000 people. We can see the capital of the region, Ponta Delgada, in the bottom left of the image. The main transport hub of the Azores, João Paulo II de Ponta Delgada International Airport, is clearly visible in the same part of the image. Tourism is an important industry for the islands, with visitors flocking to enjoy the unspoilt beaches and breathtaking landscapes, from the geysers of São Miguel to the natural waterfalls of Flores.

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Figure 53: This image, which was captured on 8 September 2016, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2016), processed by ESA, CC BY-SA 3.0 IGO)

- Known locally as the Green Island, São Miguel is the most populous of the islands and amidst the lush foliage, volcanic craters, and freshwater lakes, visitors are spoilt for choice when it comes to visual attractions.

- The largest freshwater lake in the Azores, Lagoa das Sete Cidades, can be seen in the top left of the image. It lies in a large volcanic crater and consists of two lakes: Lagoa Azul and Lagoa Verde. On the right of the image we can see Furnas Lake, in the Furnas Valley, famous for its volcanic cones. The volcanic landscape of the island has even influenced local cooking methods. Cozido das Furnas, a stew-type dish, is prepared by lowering a pot filled with meat and vegetables into the hot springs dotted around the valley, and leaving it to cook for around five hours.

- The Azores islands are rich in terms of flora and fauna, and are home to a large number of resident and migratory bird populations. Efforts are being made to restore and expand the laurel forests typical of the Macaronesian islands (an area covering the archipelagos of Madeira, Azores, Canary Islands and Cape Verde) as only around 2% of the native laurel forest remains on the islands.

- ESA, in collaboration with the French Space Agency, CNES, is organizing a symposium on 25 years of progress in radar altimetry, which will be held in Ponta Delgada from 24–29 September. With global sea-level rise a global concern, the symposium will focus on the advances made in our understanding of the open ocean, the cryosphere, and coastal and land processes. The annual meeting of the Ocean Surface Topography Science Team and the International DORIS Service Workshop will also be held in the same week.

• September 18, 2018: Thales Alenia Space, the joint company between Thales (67%) and Leonardo (33%), announced today that it has signed a contract with the European Space Agency (ESA) to provide operations, maintenance and upgrade services for the PDGS (Payload Data Ground Segment) supporting the Sentinel-2A and -2B Earth observation satellites. The service contract is worth 29 m€ for the period from May 2018 to December 2021. It is being carried out for the European Commission as part of the Copernicus program, in particular the ground segment subsystem of the CSC (Copernicus Space Component). 71)

- The two Sentinel-2 satellites with optical sensors continuously scan the Earth's surface. Together, they provide updates images of the entire land surface of our planet in five days, with a resolution of 10 to 60 meters. These images are mainly used to monitor vegetation, bodies of water, soil and coastal zones. They are also used to observe and/or help prevent natural disasters, including floods, volcanic eruptions, landslides, etc.

- Open to competitive bidding in Europe, the contract was won by Thales Alenia Space at the head of a consortium that comprises Telespazio, in charge of the integration and testing of new software versions, and its subsidiary Telespazio France, in charge of operations seven days a week, security and performance tools. Other partners are Thales Services (France), Advanced Computer Systems (part of the Exprivia Group) (Italy), Deimos Space (Spain) and C-S Systèmes d'information (France), all such companies forming with Thales Alenia Space as prime contractor to ESA the consortium having developed the PDGS.

- The PDGS contract, won in 2011, involves the reception of images (directly from S-2A and S-2B, or relayed by the EDRS satellite), and their processing, archiving and cataloging, plus distribution to users around the world. Since entering service in 2015, this system has supported the exchange of nearly 750 terabytes of data per year, or more than 250,000 images downloaded by users every month. These volumes will soon double with the commissioning of L2A image production (including atmospheric correction), making the Sentinel-2 PDGS the most highly used Earth observation data processing and exchange system in the world.

- This contract marks the latest major success for the Space Alliance, formed by Thales Alenia Space and Telespazio. The Space Alliance performs a primary role in Copernicus, serving as an essential partner in the development of the systems as well as in the various applications of the satellite program.

• August 27, 2018: Water is crucial to life on Earth. But today, its overexploitation and pollution present challenges for the environment, economies and global living standards. These issues are addressed by the United Nations' SDGs (Sustainable Development Goals) and the annual World Water Week, which runs from 26–31 August 2018 in Stockholm. 72)

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Figure 54: ESA's SMOS mission was launched in 2009 to provide global observations of soil moisture and ocean salinity – two important variables in Earth's water cycle. While this novel Earth Explorer satellite continues to advance our understanding of the planet, it is also showing considerable potential for real-world applications to improve everyday life (image credit: ESA/Cesbio) 73)

- World Water Week provides an ideal opportunity for thousands of participants from academia, industry and government to exchange ideas on this year's theme of "water, ecosystems and human development". Organized by the Stockholm International Water Institute, the week-long forum promotes collaborative action to help solve the looming water crisis. The event takes place as Europe recovers from an exceptionally dry and hot summer, which caused a drought in northern countries such as Sweden and Denmark (Ref. 72).

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Figure 55: With temperatures soaring and no rain to speak of, Europe is in the grip of a heatwave. As well as the havoc that wildfires have caused in countries such as the UK, Sweden and Greece, the current heat is scorching our land and vegetation. These two images from the Copernicus Sentinel-2 mission show agricultural fields around the town of Slagelse in Zealand, Denmark. The image from July 2017 shows lush green fields, but as the image from this July shows, the heat and lack of rain has taken its toll on the health of the vegetation. This year's summer weather means that the same comparison could be made for many other parts of Europe (image credit: ESA, the image contains modified Copernicus Sentinel data (2017–18), processed by ESA, CC BY-SA 3.0 IGO) 74)

- As a participant at the conference, the European Space Agency (ESA) is co-convening a session on the use of Big Data and Earth observation for the monitoring of SDG 6 (Clean water and sanitation). ESA recognizes the urgency of the water-related Sustainable Development Goals.

- Water scarcity affects more than 40 percent of the world's population, and one in four people is likely to live in a country suffering from chronic or recurring shortages of fresh water by 2050 due to climate change and other causes, according to the United Nations. The World Economic Forum's Global Risks Report 2018 cites water crises as posing one of the five biggest risks to society.

- "World Water Week is the ideal occasion to share information about an increasingly scarce resource while we continue working with our satellite data users to develop sustainable water-use practices through innovative projects," says Benjamin Koetz, a scientist who develops new applications for ESA's Earth Observation Program directorate.

- Satellites are an essential tool to map and monitor bodies of water from space. Optical and radar instruments can identify changes in area, and spectrometers measure water quality by applying algorithms to the color of water. ESA's Soil Moisture and Ocean Salinity (SMOS) mission also maps soil moisture as a means of providing an early-warning system for droughts and extreme weather events.

- Responding to the pressing need for water information in African countries, ESA's TIGER and Earth Observation for Sustainable Development (EO4SD) initiatives are supporting national and cross-border water authorities in using satellite data to manage water supplies.

- For TIGER, South Africa's Stellenbosch University applies machine-learning software to data from the Copernicus Sentinel-1 and Sentinel-2 missions to monitor water levels in the Theewaterskloof Dam, a major water source for the Western Cape region, which includes the city of Cape Town.

- ESA has released its first comprehensive database listing activities undertaken by the Agency and its service providers to make the Sustainable Development Goals a reality. Among these activities is the Grey Water Recycling System, operated at the Concordia base in Antarctica. Water previously used for washing or cooking is recycled in a multistep process involving ceramic honeycomb peppered with holes 700 times finer than a strand of human hair, followed by a pair of membranes that yield clean water. The project addresses four SDGs and is overseen by ESA's Human and Robotic Exploration (HRE) directorate. The same kind of technologies were applied in a university in Morocco to provide fresh water and energy to 1200 students, from groundwater rich in nitrates and fertilizer and with solar and wind energy.

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Figure 56: A river delta usually leads to the open sea, but the delta formed by the Okavango River is different. After rising in Angola and flowing through Namibia, the river meanders into Botswana, where it branches out to create an inland delta – one of the world's most important wetlands. Wetlands, both coastal and inland, are important for people and the environment. Their many benefits include acting as natural safeguards against disasters, protecting communities most vulnerable to the devastating effects of floods, droughts and storm surges. They also provide a habitat for a multitude of animals and plants, and filter and store water. The Copernicus Sentinel-2A satellite captured this image of the Okavango Delta on 2 December 2016. It has been processed in false color to highlight variations in the water cover and differences in vegetation (image credit: ESA, the image contains modified Copernicus Sentinel data (2016), processed by ESA, CC BY-SA 3.0 IGO) 75)

- Every year, 2 February marks World Wetlands Day. It commemorates the Convention on Wetlands also known as the Ramsar Convention, which was signed on 2 February 1971 to provide a framework for national and international cooperation for the conservation and use of wetlands and their resources. This year's theme is ‘Wetlands for Disaster Risk Reduction'.

- Well-managed wetlands provide resilience for communities against extreme weather and help to minimize the damage from these hazards. - Coastal wetlands such as mangroves protect against flooding and serve as buffers against saltwater intrusion and erosion. Inland wetlands such as floodplains, lakes and peatlands and deltas like Okavango can reduce the risk of drought.

- The Okavango Delta, a World Heritage site, includes permanent swamps that cover about 15,000 km2 during the dry season but can swell to around three times this size, providing a home for some of the world's most endangered species of large mammals. In sharp contrast, the surrounding Kalahari Desert is a lifeline for local communities and wildlife alike – and therefore it is extremely important that it is well managed.

- Through the GlobWetland Africa project, ESA and the African team of the Ramsar convention help to use satellite observations for the conservation, wise-use and effective management of wetlands in Africa. Through the project, African stakeholders are provided with methods and tools to fulfil their commitments to Ramsar.

• July 27, 2018: The Copernicus Sentinel-2 satellite takes us over Sharm El Sheikh, Egypt. Famous as a resort on the southern tip of the Sinai Peninsula, this coastal strip along the Red Sea is peppered with bars, restaurants and hotels. The ancient Greeks and Romans are thought to have taken their holidays in Egypt as long ago as the 4th century BC. 76) 77)

- This striking true-color image shows the Gulf of Aqaba at the top center, feeding into the Red Sea – home to some of the hottest and saltiest seawater in the world. The Red Sea is connected to the Mediterranean Sea via the Suez Canal, one of the world's busiest waterways.

- Usually an intense blue-green, as captured in this image, the Red Sea is known, on occasion, to turn reddish-brown owing to algal blooms, which change the color of the sea when they die off.

- The area offers many opportunities for diving. In the center of the image we can see a series of coral reefs, which host rich marine life. The variations in the color of the water surrounding the islands and in the right of the image represent the depth of water – the lighter areas show more shallow waters than the vast expanse of deep blue, which dominates the image.

- In the top-right of the image, we can see the western tip of mainland Saudi Arabia – the beautiful and uninhabited sandy cape of Ras Al-Sheikh Hameed. Here, the red color represents areas with higher levels of moisture in an arid, desert landscape, while the white color represents salt.

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Figure 57: Sentinel-2 captured this image of Sharm El Sheikh,Egypt and the Gulf of Aqaba on 11 April 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA , CC BY-SA 3.0 IGO)

• July 20, 2018: The Copernicus Sentinel-2 satellite takes us over the city of Valencia and its stunning blue coast. Situated on the east coast of the Iberian Peninsula, Valencia is the third largest city in Spain after Madrid and Barcelona. 78)

- The city is visible in the center of the image, flanked by the Mediterranean Sea on one side and overlooked by the mountains of the Sierra Calderona to the north. As a significant cultural center for the country, it is home to the futuristic City of Arts and Sciences complex, which also hosts Oceanografic – the biggest aquarium in Europe.

- Just 10 km south of the city, this true-color image shows us the Albufera freshwater lagoon in green. Separated by a narrow strip of coastline featuring sand dunes and Mediterranean pine forest, three canals connect the lagoon and surrounding wetlands with the sea.

- The area is home to huge numbers of both migratory and resident birds, including rare species such as Eurasian Bittern. The area is also thought to be the home of the world-famous Paella dish, with the traditional rice used for the dish grown in the surrounding fields since the 19th century.

- On the right of the image, amidst the waves and popcorn clouds, we can see a boat, possibly travelling to the port of Valencia from one of the nearby Balearic Islands – a popular route for tourists and residents of the city alike.

- The region of Valencia is famous for the diversity of its landscapes, covering mountains, beaches, wetlands and semi-arid desert environments within a total area of less than 25,0000 km2. This diversity is clearly highlighted in the Sentinel-2 image.

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Figure 58: This image was captured on 9 August 2017 with the Sentinel-2 satellite, it is also featured in the Earth from Space program (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA , CC BY-SA 3.0 IGO)

• July 17, 2018: A huge iceberg drifted perilously close to the west Greenland coast causing fears that if it breaks up, waves could swamp the village of Innaarsuit. 79)

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Figure 59: This satellite image, captured by Sentinel-2A on 9 July 2018, shows a huge iceberg perilously close to the village of Innaarsuit on the west coast of Greenland. If the berg breaks apart, waves resulting from the falling ice could wash away parts of the village (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA)

- The 169 residents of Innaarsuit in West Greenland are relatively used to seeing large icebergs floating by, but weighing around 10 million tons, this is reported to be the largest in memory. With chunks of ice calving from the iceberg, a number of residents were evacuated amid fears of a bigger break up. The local power plant is also on the coast so waves could also potentially shut down the village's power supply. However, there are recent reports that strong winds from the south have started to push the berg to the north. The image also shows several other large icebergs in the vicinity.

• July 6, 2018: The Copernicus Sentinel-2A satellite takes us over the capital of Iceland, Reykjavik. As a volcanic island famous for its volcanoes, glaciers, lakes, lava and hot springs, Iceland attracts tourists all year round with its vast array of natural wonders. 80)

- The image of Figure 60, which was captured on 1 November 2017, is also featured on the Earth from Space video program.

- In the upper left part of the image, ‘kettle holes' are visible as small dark green dots scattered across the reddish brown area. Kettle holes are formed when blocks of ice break away from glaciers and then become buried in outwash. When these buried blocks of glacier ice melt away they leave behind holes, which become filled with water and turn into kettle hole lakes. They are often found in areas that were covered in ice during the last ice age, which ended around 12 000 years ago. Kettle holes are common in Michigan in the United States, as well as in parts of Germany, Austria and the UK.

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Figure 60: This true color image shows us the small city of Reykjavik, home to around 120 000 people, and seen in the lower central part of the image. The port town of Akranes, 20 km north of the capital, is also shown in grey in the center of the image. In between the two lies Mount Esja, standing just over 900 m tall, and providing a dramatic backdrop to the capital (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA , CC BY-SA 3.0 IGO)

• June 29, 2018: For Asteroid Day, the Copernicus Sentinel-2A satellite takes us over the Gosses Bluff crater in the Northern Territory of Australia. The crater is visible in the left center of the image and it is about 22 km in diameter (Figure 61). It was most likely formed 140 million years ago by the impact of a large comet or meteorite slamming into the surface of Earth. 81) 82)

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Figure 61: Sentinel-2A captured the image of a crater in Australia on 4 February 2016 (image credit: ESA, the image contains modified Copernicus Sentinel data (2016), processed by ESA, CC BY-SA 3.0 IGO)

- This false-color image shows an extremely dry area with some vegetation visible in reddish colors along the rivers and lakes. The intense colors of the image represent the mineral composition of the land surface, which is clearly visible owing to the lack of vegetation. Azurite is one of the minerals mined here.

- A series of low hills and drainage structures can be seen in the lower part of the image, a result of erosion over the years. The West MacDonell Ranges can be seen in the upper section of the image and part of the Petermann Ranges are shown in the lower section.

- The crater is around 200 km west of Alice Springs, famous for being the gateway to the Red Center, Australia's interior desert region.

- Asteroid Day brings people from around the world together to learn about asteroids, the impact hazard they may pose, and what we can do to protect our planet, families, communities, and future generations from asteroid impacts. It takes place on 30 June each year, which is the anniversary of the largest asteroid impact in recent history, the 1908 Tunguska event in Siberia.

• 22.06.2018: The Copernicus Sentinel-2A satellite takes us over Lake Huron, the second largest of the five Great Lakes of North America. Bound on the north and east side by the Canadian province of Ontario and on the south and west side by the state of Michigan in the U.S., Lake Huron was the first of the Great Lakes to be seen by Europeans in 1615. 83) 84)

- This image shows signs of sediments and algae bloom along the coast, one of the consequences of intensive agricultural activity in a region that responds to the ongoing demand for produce.

- Lake Huron is around 330 km long from northwest to southeast. Covering an area of over 244,000 km2 and containing around 22,600 km3 of water, together the Great Lakes form the largest connected area of fresh, surface water on Earth. The only places that hold more fresh water are the polar ice caps and Lake Baikal in Siberia.

- Many islands lie in the northeastern part of the lake, with Heisterman Island, North Island and Middle Grounds Island, home to Wild Fowl Bay State Park, shown on the bottom left of the image.

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Figure 62: The image, which was captured on 1 December 2017, highlights the dominance of agricultural production in the region where conditions are ideal for cultivating corn, soybeans and hay. The colored blocks in the image show a grid-like structure for growing crops, typical of American agricultural practice (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• June 15, 2018: At 8485 m high, Makalu is the fifth highest mountain in the world. The iconic pyramid-shaped mountain can be seen just to the right of the center of the image (Figure 63). It is situated on the border between Nepal and China, about 19 km southeast of Mount Everest, which is in the top left of the image. 85) 86)

- Because of the mountain's knife-edge ridges and its remote position, which leaves it exposed to the elements, it is viewed by many as one of the world's most difficult mountains to climb.

- Nevertheless, Swedish explorer, mountaineer and climate campaigner, Carina Ahlqvist, led a climb this year to raise awareness of climate change and to support ESA's Climate Change Initiative. During the expedition, scientists collected measurements to help validate data from the Copernicus Sentinel-1 radar mission that are used to study natural hazards such as rock falls and landslides in mountainous regions. The team also surveyed the Barun glacier, which lies at the base of Makalu, to help understand its history and therefore the past climate in this region.

- Unfortunately, Carina was struck with snow blindness and had to be evacuated just 300 m from Makalu's summit. She is now safe and well and the data collected during the expedition are being used to further understand the dynamics of this remote region and how it is being affected by climate change.

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Figure 63: Mount Makalu in the Himalayas is pictured in this Copernicus Sentinel-2B image acquired on 9 December 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• June 8, 2018: Copernicus Sentinel-2 images from 23 May and 7 June 2018 show changes in lava flow from the Kilauea volcano on Hawaii's Big Island. It is estimated that around 600 homes have been destroyed in one of the volcano's most destructive eruptions in modern times. According to Hawaii County Mayor, Harry Kim, Kilauea has never destroyed so many homes in such a short time. It is one of five volcanoes on the Big Island and is one of the world's most active volcanoes. 87)

- While the Sentinel-2 mission mainly provides information for agricultural and forestry practices and to map changes in land cover, its images of disasters such as volcanic eruptions can be used to help assess damage.

Figure 64: The Sentinel-2 mission has imaged changes in lava flow from the Kilauea volcano in Hawaii (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• May 22, 2018: Covering 3000 km2, the Zambezi Delta in Mozambique is one of the most diverse and productive river delta systems in the world. This unique wetland, which is protected under the Ramsar Convention on Wetlands, features a broad alluvial plain with vast mosaics of grassland, woods, deep swamps and extensive mangroves. Recognized as a global biodiversity conservation hotspot, this remarkable delta is home to a myriad of wildlife, from big mammals such as buffaloes, lions and elephants to water birds such as fish eagles and flamingos, to marine species such as dolphins and freshwater fish. As well as this rich biodiversity, this extraordinary delta not only provides a source of food for Mozambique, but also protects the coast from flooding. 88)

- While the Zambezi River Delta is an example of a healthy ecosystem, biological diversity is declining around the world. It is estimated that between 100 and 150 species disappear every day. The International Day for Biological Diversity is held every 22 May to increase understanding and awareness of biodiversity issues such as this. Ratified by 196 nations, the Convention on Biological Diversity is the international legal instrument for the conservation of biological diversity and the sustainable use of its components.

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Figure 65: Satellites observing Earth have an important role to play as images can be used to assess the health of important ecosystems and show how they may be changing. This image was captured by the Copernicus Sentinel-2A satellite on 28 September 2016 (image credit: ESA, the image contains modified Copernicus Sentinel data (2016), processed by ESA, CC BY-SA 3.0 IGO)

• May 18, 2018: The Copernicus Sentinel-2 mission takes us over the Bay of Mont Saint-Michel in northern France. -Lying between Brittany to the west and Normandy to the east, this remarkable bay, which is listed as a UNESCO world heritage site, sees some of the biggest tides in continental Europe. There can be up to 15 m difference between low and high water. When spring tides peak, the sea recedes about 15 km from the coast and when it returns it does so very quickly, making it a dangerous place to be. Sentinel-2 captured this image when the tide was out so that the vast area of sand dunes is exposed cut by meandering channels of shallow water. Three rivers empty into the bay: the Couesnon, the Sée and the Sélune. 89)

- The famous rocky islet of Mont Saint-Michel, visible as a small dark spot in the south of the bay, is about 1 km from the mouth of the Couesnon. Home to a Benedictine monastery and village, Mont Saint-Michel is also a UNESCO world heritage site and a mecca for tourists.

- The bay, however, has been prone to silting up in the last couple of centuries. Actions by man, including farming and the building of a causeway to the island monastery, have added to this problem. A major campaign has ensured that Mont-Saint-Michel preserves its maritime character and remains an island. The main river into the bay, the Couesnon, for example, is being left to flow more freely so that sediments are washed out to sea.

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Figure 66: This Sentinel-2 image of the Bay of Mont Saint-Michel was captured on 21 June 2017, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• May 11, 2018: The Copernicus Sentinel-2B satellite takes us over Alaska's Columbia Glacier, one of the most rapidly changing glaciers in the world. Over the last three decades, this tidewater glacier has retreated more than 20 km and lost about half of its total thickness and volume. The changing climate is thought to have nudged it into retreat in the 1980s, resulting in its end – or terminus – breaking off. 90) 91)

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Figure 67: Sentinel-2B captured this false color image on 5 August 2017. The glacier flows down the snow-covered slopes of the Chugach Mountains into the Prince William Sound in southeast Alaska (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

- The terminus had previously been supported by a moraine, which is an accumulation of sediment and rock that served as an underwater barrier, helping to keep the glacier stable and insulate it from seawater. With this barrier gone, glacial dynamics took over and it began to flow to the ocean faster, calving large icebergs into the Sound. As this satellite image shows, many icebergs can be seen in the Sound.

- This one glacier accounts for nearly half of the ice loss in the Chugach Mountains. However, researchers believe that the Columbia Glacier will stabilize again – probably in a few years – once its terminus retreats into shallower water and it regains traction, which should slow the rate of iceberg calving.

• May 04, 2018: Reminiscent of an artist's pallet, this is the Emi Koussi volcano in northern Chad, imaged by the Copernicus Sentinel-2B satellite. Emi Koussi lies at the southeast end of the Tibesti Mountains. At almost 3500 m, this pyroclastic shield volcano rises high above the surrounding sandstone plains. It is not only the highest mountain in Chad, but also the highest in the Sahara. Calderas, or depressions, can be seen nestling in the cap of the volcano. These are a result of magma erupting quickly and the surface collapsing into the partially emptied magma chamber. Emi Koussi is extinct and it is not known when it last erupted. 92)

- The lack of vegetation allows wind and water to carve long grooves in the rock. These grooves can be 30 m deep and several kilometers long. The Copernicus Sentinel-2 satellites carry innovative high-resolution multispectral cameras with 13 spectral bands. Processing the image here reveals differences in the minerals of the rock. For example, the green around the cone of the volcano is old lava, while sandstone in the surrounding area appear in reds and yellows.

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Figure 68: This image of the Emi Koussi volcano, which was captured on 27 November 2017, is also featured on the Earth from Space video program (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• April 20, 2018: Henderson Island lies in the South Pacific, about halfway between New Zealand and Chile. As one of the best examples of a coral atoll, Henderson Island is a UN World Heritage site and one of the world's biggest marine reserves. However, while this remote, uninhabited, tiny landmass may look idyllic and untouched by humans, it's one of the most plastic-polluted places on Earth (Figure 69). 93) 94)

- It is estimated that around 10 million tons of plastic ends up in the oceans every year. Carried by currents, it can form rubbish patches or eventually be washed up on shores far from where it entered the ocean. On Henderson, for example, items from as far afield as Russia, USA, Europe and South America have been found.

- Ocean plastic has serious consequences for wildlife and the environment. Marine animals not only get caught up in this plastic but also ingest it. Even when it has been broken down into microfragments by weathering and waves, it still endangers animals and also enters the food chain, with unknown long-term consequences for animal life and our own health.

- Celebrated every 22 April since 1970, Earth Day demonstrates support for environmental protection. This year, Earth Day is dedicated to providing information and inspiration needed to change our attitude towards plastic.

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Figure 69: The Sentinel-2B satellite captured this image of Henderson Island on 22 March 2018 (image credit: ESA, this image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• April 13, 2018: The Copernicus Sentinel-2A satellite takes us over southern India to the capital of Telangana: Hyderabad (Figure 70). Home to almost seven million people and covering about 650 km2, Hyderabad is one of the largest metropolitan areas in India. It lies on the banks of the Musi River, which can be seen running across the middle of the image. Although steeped in history, this rapidly growing metropolis has become a hub of commerce and an international center for information technology, earning it the nickname of Cyberabad. 95) 96)

- While several lakes can be seen in the image, they are gradually being lost. It has been said that the city once had 7000 lakes, but there are now only about 70 and they are being subjected to pollution as the city expands and develops. Even the city's most famous lake, the heart-shaped Hussain Sagar, is blighted with pollution from agricultural and industrial waste and municipal sewage.

- The two identical Copernicus Sentinel-2 satellites carry high-resolution cameras working in 13 spectral bands. Images from the mission can be used to monitor pollution in lakes, changes in vegetation and urban growth.

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Figure 70: Captured on 14 May 2017, the image has been processed to highlight the different features in and around the city. The yellow and browns show the built-up center while the light greens in the surroundings show arid fields. The shades of darker green depict vegetation and areas covered by trees. Interestingly, the bright blue, which appears, for example, along the Musi River and near other water bodies, is also vegetation such as parkland and grass (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• March 30, 2018: Figure 71 is a Copernicus Sentinel-2B image of Egg Island in the Bahamas, appropriate for the Easter season. Covering just 2070 km2, Egg Island is officially an islet. This tiny uninhabited patch is at the northwest end of the long thin chain of islands that form the Eleuthera archipelago, about 70 km from Nassau. Its name perhaps originates from the seabird eggs collected here. 97) 98)

- The image, which Sentinel-2B captured on 2 February 2018, shows the sharp contrast between the beautiful shallow turquoise waters to the southwest and the deeper darker Atlantic waters to the northeast. Ripples of sand waves created by currents stand out in the shallow waters. These shallow waters are a natural nursery for sea turtles and other sea life. Any disturbance to this delicate ecosystem could spell disaster for wildlife. In fact, Egg Island was recently at risk of being developed as a cruise ship port, which would have meant dredging the seabed and destroying coral reefs. Fortunately, this plan didn't take hold because of the damage it would cause to the environment.

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Figure 71: Sentinel-2B image of Egg Island, Bahamas, acquired on 2 February 2018 (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• March 26, 2018: Sand and dust stirred up by desert storms in north Africa have caused snow in eastern Europe to turn orange, transforming mountainous regions into Mars-like landscapes. This Copernicus Sentinel-2A image of Libya (Figure 72) captured on 22 March shows Saharan dust being blown northwards across the Mediterranean Sea. Lifted into the atmosphere, the dust was carried by the wind and pulled back down to the surface in rain and snow. It reached as far afield as Greece, Romania, Bulgaria and Russia. While the orange-tinted snow baffled skiers, meteorologists say this phenomenon occurs about every five years. 99)

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Figure 72: This Sentinel-2A image of Libya, captured on 22 March, shows Saharan sand and dust being blown northwards across the Mediterranean Sea. Lifted into the atmosphere, the dust was carried by the wind reaching as far afield as Greece, Romania, Bulgaria and Russia. While the orange-tinted snow baffled skiers, meteorologists say this phenomenon occurs about every five years (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• March 23, 2018: The Dutch are now starting to see their famous spring flowers poke through the winter soil, but a few weeks ago it was a different story as a cold snap took grip. — This Copernicus Sentinel-2 image from 2 March 2018 shows Amsterdam and the IJmeer and Markemeer freshwater lakes covered by a thin layer of ice. As famous as the Netherlands is for flowers, it's arguably equally renowned for ice skating. While the cold snap caused havoc throughout much of Europe, the Dutch were busy dusting off their skates and eager to hit the ice. The ice on these big lakes was much too thin to skate on, but some canals in Amsterdam were closed to boats to give the ice a chance to thicken and skaters took what is now a relatively rare opportunity to enjoy a national pastime. 100) 101)

- A possible consequence of climate change, the Netherlands doesn't see the ice that it used to. The Royal Netherlands Meteorological Institute rates winters using an index: those scoring above 100 are considered cold. Between 1901 and 1980, there were seven winters above 200 – very cold. The last time the index exceeded the magical 100 mark was in 1997. In fact, this was also the last time the weather was cold enough for an ‘Elfstedentocht': a 200 km skating race between 11 towns in the north of the country. In 2014, for the first time since measurements began, the index fell to zero.

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Figure 73: While people enjoyed the ice below, this Sentinel-2 image, acquired on 2 March 2018, allows us to view the beauty of this short-lived layer of ice from above (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• Marking the International Day of Forests on March 21, 2018, this Copernicus Sentinel-2 image shows an area of Bolivia that was once covered by trees but has now been cleared for resettlement schemes and agriculture. 102)

- Bolivia's city of Santa Cruz can be seen at the mid-left of Figure 74. One of the fastest growing cities in the world, this important commercial center lies on the Pirai River in the tropical lowlands of eastern Bolivia. To the east of the city, and particularly east of the Guapay River, or the Río Grande, a huge patchwork of agricultural fields can be seen. Back in the 1960s this was an area of largely inaccessible thick Amazon forest. However, as an area of relatively flat lowland with abundant rainfall, it is suited to farming.

- As part of a drive to develop and improve the economy, there has been rapid deforestation since the 1980s to accommodate programs to resettle people from the Andean high plains and develop the area for agriculture, particularly for soybean production. This has resulted in the region being transformed from dense forest into a large mosaic of fields. As well as countless rectangular fields, radial features can be seen where individual farmers have worked outwards from a central hub of communal land.

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Figure 74: This image was captured by the Copernicus Sentinel-2A satellite on 30 September 2017, and processed in false color (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• March 20, 2018: The traditional way of mapping Earth's geology and mineral resources is a costly and time-consuming undertaking. While satellites cannot entirely replace the expert in the field, they can certainly help – as a recent effort in Africa shows. Geological maps identify different types of rock, faults, groundwater and deposits. They are not only essential for building infrastructure and assessing risk, but also important for locating and mining natural resources. 103)

- ESA has recently supported a pan-African initiative to collect, interpret and disseminate satellite information on geology and mineral resources such as metallic ores.

- This ESA-funded effort has paved the way for the German geo-information company GAF (Munich) to help the African Mineral Geoscience Initiative. The aim of the initiative, which is led by the African Union Commission and supported by the World Bank Group, is to catalog Africa's geology and mineral resources.

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Figure 75: Details of the geological mapping layers for the Western Sahara demonstration area. From top to bottom: Sentinel-2 natural color composite, Sentinel-2 principal components analysis, SRTM (Shuttle Radar Topography Mission)-based elevation and the resulting geological map at 1:50000 scale (image credit: GAF)

- This task is made somewhat easier thanks to freely available data from the Copernicus Sentinel-1 and Sentinel-2 missions, as well as information from other satellites such as NASA's Shuttle Radar Topography Mission and the US WorldView-3 mission of DigitalGlobe.

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Figure 76: Geologic mapping: ESA has recently supported a pan-African initiative to collect, interpret and disseminate satellite information on geology and mineral resources. Through this ESA-funded activity, the German geo-information company GAF assisted AMGI (African Mineral Geoscience Initiative) with satellite-based information. The aim of AMGI is to catalogue Africa's geology and mineral resources. As this example of Namibia shows, data from the Copernicus Sentinel-1 and Sentinel-2 missions, as well as data from other satellites such as NASA's Shuttle Radar Topography Mission and the US WorldView-3 mission were used to map the area (image credit: GAF)

- The idea is to produce geological maps for various climatic zones and different types of geology, especially in areas where data are scarce, not sufficiently detailed or outdated.

- Initial results show that while arid and semi-arid areas can be mapped accurately, tropical areas are more of a challenge. This is because these regions are typically covered with vegetation, which optical sensors cannot see through to gain information on the ground beneath. In these regions, radar and ground elevation data have been used, so structural information such as river networks form the basis of the maps.

- Overall, however, the initiative has shown how large areas can be mapped consistently and efficiently, which is of particular interest for surveying regional geology and for mining minerals.

- Francisco Igualada, senior mining specialist at the World Bank said, "Earth observation is one of the major sources of information for new and improved geological mapping. The results of the project demonstrate that satellite imagery combined with existing geophysical data is a fast, effective and efficient way to support the production and interpretation of geological maps at all scales – from low-scale reconnaissance mapping to detailed surveys – all of which are relevant for mineral exploration."

- Moreover, these results are important because it is envisaged that an accurate and comprehensive geological catalog will attract future investments in Africa.

• March 15, 2018: The Copernicus Sentinel-2A satellite takes us over the Japanese capital of Tokyo. Tokyo lies on the eastern shore of the island of Honshu, the largest of Japan's four main islands. Greater Tokyo, which fans out further to the north and northwest than this image shows, is home to almost 38 million people, making it the largest megacity in the world. 104) 105)

- The grey tones of this urban conurbation dominate the image and are in sharp contrast to the dark greens of the rugged mountains that flank the city to the west. The city center lies mainly to the south of the Arakawa River, which empties into Tokyo Bay. The bay can be seen in the bottom right of the image (Figure ). While many boats are visible in the bay, so is the Aqua-line, which is a combination of a bridge and a tunnel that spans the bay. The Aqua-line can be seen on the east side of the bay as a bridge that then disappears underwater as a tunnel. It has an overall length of almost 23.7 km, almost 10 km of which is tunnel – the fourth longest underwater tunnel in the world. A building that provides ventilation, as well as serves a rest stop, appears as an island-like structure above the tunnel.

- Nowadays, more than half of the global population live in urban areas and, as more people flock to cities, expansion and development needs to be planned and monitored. The Copernicus Sentinel-2 mission offers essential information for urban planners and decision-makers around the world.

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Figure 77: This Sentinel-2A image of Tokyo was captured on 8 May 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• March 13, 2018: The EDRS–SpaceDataHighway has now begun regularly relaying Earth images from Sentinel-2A, which marks the last of four Copernicus satellites in orbit being brought under the EDRS service. After several months of rigorous testing, the system has added the last ‘color vision' Sentinel to the list of Sentinels it serves, bringing the satellite's vibrant images to Earth faster than ever and completing the full set of four. 106) 107)

- EDRS (European Data Relay System) will be a unique system of satellites permanently fixed over a network of ground stations, with the first – EDRS-A – already in space. These nodes lock on to low-orbiting satellites with lasers and collect their data as they travel thousands of kilometers below, scanning Earth. EDRS then immediately sends the data down to Europe from its higher position hovering in geostationary orbit at around 35 800 km, acting as a go-between. 108)

- This process allows the lower satellite to continuously downlink the information it is gathering, instead of having to store it until it travels over its own ground station. That way, it can send down more data, more quickly.

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Figure 78: The services offered by the SpaceDataHighway enable users to transfer their data (imagery, video, voice ...) from their Earth Observation satellites, UAVs, multimission aircraft by means of optical communication via EDRS-A and EDRS-C geostationary satellites to receiving ground stations located in Europe (image credit: Airbus)

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Figure 79: A false-color image showing part of the Ganges Delta in south Asia, captured by the Copernicus Sentinel-2B satellite and relayed by EDRS-A on 27 October 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• March 2, 2018: Although this image of Figure 80 might look more like the surface of Mars, it was actually captured by the Copernicus Sentinel-2 mission and shows southeast Namibia and the western edge of the Kalahari Desert. 109) 110)

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Figure 80: This image of the Kalahari Desert was captured by Sentinel-2 on 28 July 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

- Namibia is famous not only for its stunning desert landforms but also because these deserts offer clues to the history of tectonic plate movement in this part of Africa. The Namib Desert, which runs along Africa's southwestern coast, is said to be the oldest desert in the world. While this image was taken further east – over part of southeast Namibia – the striking orange–russet tones are also down to the semi-arid climate in this remote region.

- The Kalahari, which covers much of Botswana, parts of South Africa and part of southeast Namibia is not a true desert as it receives too much rain, but it is an area of ancient fossilized sand dunes. Some of these dunes, also known as sand sheets, can be seen running across the top-right corner of the image and appear surprisingly parallel and uniform. It is thought that these dunes formed between 2,500,000 and 12,000 years ago, and have been fixed ever since.

- To the east, the landscape also looks like an alien orange world and is dominated by ridges, escarpments and dry lake beds known as salt pans. Roads cutting sharply across the landscape are a reminder that this region is not entirely unpopulated.

• Today, 16 February 16 2018, upwards of 20% of the world's population will be celebrating the Chinese New Year, also known as the Spring Festival. According to the traditional Chinese calendar, which is based on the lunar cycle and the position of the Sun, the New Year changes each year, but always falls between 21 January and 20 February. There are 12 Chinese zodiac animals that represent years, and 2018 is the year of the dog. 111)

- Marking this special day, we take a look at a Sentinel-2 image of Beijing, the capital of China. It is one of the most populous cities in the world, with over 21 million people, but during the New Year, millions travel from the big cities back to their hometowns to spend the holiday with their families in what is considered the world's largest annual migration.

- Beijing lies in northeast China at the northern tip of the North China Plain. While the city lies on flat ground, it is surrounded by mountains to the north and west (not pictured). From space, the city appears to be divided up into many squares, which is a consequence of it being one of oldest planned cities in the world. Beijing's present urban form was established in the early Ming dynasty – between 1368 and 1644 – with planning stipulating that the city should be a square encompassing nine avenues running north–south and nine running east–west.

- While this Copernicus Sentinel-2 image (Figure 81) details much of the city, a number of famous landmarks can be picked out easily. For example, lying in the heart of Beijing, the Forbidden City, one of China's largest and best preserved heritage sites, and Tiananmen Square can be seen.

- Happy Chinese Year – or Xīn nián kuài lè – to all.

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Figure 81: This Sentinel-2 image of Beijing was acquired on 3 May 2016 (image credit: ESA, the image contains modified Copernicus Sentinel data (2016), processed by ESA, CC BY-SA 3.0 IGO)

• February 2, 2018: This Copernicus Sentinel-2 image features Tunisia's capital Tunis, in North Africa, and highlights some of the country's important wetlands (Figure 82). 112) This image is featured on the Earth from Space video program. 113)

- Captured on 15 December 2017, the image shows part of the Mediterranean's Gulf of Tunis, which provides natural protection for this ancient city and busy port. The area has seen a series of settlements over the last 3000 years, but arguably the most famous is Carthage, which now forms a suburb to the northeast of the center of Tunis.

- While the image offers sharp contrast between the city's urban environment and surrounding hills and agricultural fields, it also depicts several bodies of water, which are protected under the Ramsar Convention on Wetlands.

- World Wetlands Day is celebrated every year on 2 February, and with this year's theme being Wetlands for a Sustainable Urban Future, this image of Tunis highlights how important these wetlands are to the city.

- There are seven Ramsar sites around Tunis, five of which are visible in the image. Lake Tunis can be seen close to the coast and features a causeway. It is a brackish lagoon surrounded by intertidal marshes. It offers good nesting grounds for several species of bird and wintering grounds for species such as the Greater Flamingo. Mammals include rodents and bats, and it is an important source of food, a spawning ground and a nursery for several fish species. The main human activity carried out is fishing, regulated according to its protected status.

- The shallow lake of Sebkhet Sejoumi is west of Lake Tunis and is one of the largest water reservoirs protecting the capital from floods. Unlike other sebkhets – or salt lakes – in the area, Sejoumi retains some water all year and is therefore particularly important for wildlife in the summer when other sebkhets dry up.

- The smaller protected lakes of Ghdir El Golla and Barrage Mornaguia can be seen further west on the outskirts of the city. To the north of the city, lies Sebkhet Ariana which loses much of its water in the summer.

- Through its GlobWetland Africa project, ESA works in partnership with the Ramsar Secretariat to use information from satellites to help conserve and manage vulnerable wetlands such as these.

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Figure 82: Sentinel-2 acquired this image of Tunis on 15 December 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• February 1, 2018: Dubbed a perfect volcano because of the symmetry of its cone, Mount Mayon on the island of Luzon in the Philippines is erupting again. With more than 30 eruptions recorded since 1616, it is one of the world's most active volcanoes. This image, which was captured by the Copernicus Sentinel-2 mission on 30 January, has been processed to show different facets of the eruption. The Sentinel-2 satellites each carry a high-resolution camera that images Earth in 13 spectral bands. Here we see the volcano in natural color and then in false color, which by highlighting vegetation in red shows the damage caused by lava. Then two shortwave infrared bands reveal the hot lava spilling from the cone.

Figure 83: This Sentinel-2 image of the Mayon volcano was acquired on 30 January, showing the different facets of the eruption (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• January 25, 2018: The Yukon River rises in British Columbia in Canada and flows through Yukon Territory before entering Alaska and finally draining into the Bering Sea (total river length of 3,190 km). This image of Figure 84, recorded on 29 August 2017, shows how the river branches off into numerous channels that meander through the low-lying terrain on their way to the sea. The sandy color of these channels and of the coastal water illustrates how much sediment the river carries to the sea at this time of year. 114)

- It is estimated that 95% of all sediment transported during an average year occurs between May and September. During the other seven months, concentrations of sediment and other water-quality constituents are low. However, scientists also believe that sediment flow has increased over the last few decades because permafrost is thawing in the Yukon River Basin and ice breakup occurs earlier in the year owing to warmer air temperatures. This is important because elevated concentrations can adversely affect aquatic life by obstructing fish gills, covering fish spawning sites, and altering habitat of bottom-dwelling organisms. Metals and organic contaminants also tend to absorb onto fine-grained sediment.

- The Copernicus Sentinel-2 satellites each carry a high-resolution MSI (Multispectral Imager) camera that images Earth's surface in 13 spectral bands. While the mission is mostly used to track changes in the way land is being used and to monitor the health of our vegetation, it also provides information on the condition of coastal waters.

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Figure 84: Sentinel-2 image of the Yukon River Delta and its coastal sediment acquired on 29 August 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• January 19, 2018: The Copernicus Sentinel-2A satellite takes us over part of northern Brazil's Marajó island in Pará state (Figure 85). 115)

- Sediments discharged by the nearby Amazon River mouth (not pictured) are visible in the waters of the Atlantic Ocean north of the island.

- The land area pictured is dominated by a savannah landscape, with mangrove forests and palm swamps along the coast. The area is known for its large plantations – called fazendas – with animal husbandry. Although not native to the island, domesticated water buffalo outnumber Marajó's human population.

- ‘Popcorn' clouds are visible in the upper part of the image, formed by convection and condensed water vapor released by plants and trees during the sunny day. On the left side of the image we can see Lake Arari, the size of which fluctuates greatly between the rainy and dry seasons.

- Sentinel-2 images Earth in 13 spectral channels. Scientists can select which wavelength combinations to process over a given area to help better understand targets on the ground.

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Figure 85: The channel combination used to create this image, which was acquired on 20 July 2017, is particularly useful for identifying different vegetation types and helps us to distinguish it very clearly from inland water bodies: water appears dark blue, while vegetation appears in a variety of bright colors (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• January 12, 2018: The Copernicus Sentinel-2 mission has captured rare snowfall in northwest Algeria, on the edge of the Sahara desert (Figure 86). Part of the Sahara was covered with snow on 7 January 2018, despite the desert at times being one of the hottest places on Earth. The snow was reported to be up to 40 cm thick in some places. Although temperatures plummet during the night, snowfall is very unusual in the Sahara because the air is so dry. It is only the third time in nearly 40 years that this part of the desert has seen snow. 116)

- Most of the snow had melted by the end of the next day, but luckily the Sentinel-2A satellite happened to be in the right place at the right time to record this rare event from space. The image was acquired on 8 January.

- While snow is common in the High Atlas Mountains, the image shows that, unusually, snow fell on the lower Saharan Atlas Mountain Range. The image is dominated by the orange–brown dunes and mountains dusted with snow.

- The town of El Baydah can be seen towards the bottom left. To the east of El Baydah, a cultivated forest is visible as a red rectangle. The image, which has been processed to display vegetation in red, shows that there is very little flora in the region.

- The two Copernicus Sentinel-2 satellites each carry a high-resolution camera that images Earth's surface in 13 spectral bands. The mission is largely used to track changes in Earth's land and vegetation, so useful for monitoring desertification.

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Figure 86: Sentinel-2 image of the snow-covered Sahara desert in northwest Algeria, acquired on 8 January, 2018 (image credit: ESA, the image contains modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO)

• December 22, 2017: The Copernicus Sentinel-2 mission takes us over part of Lake Winnipeg in the Canadian province of Manitoba, with Reindeer Island visible in the lower-right part of the image of Figure 87. While our friends on the other side of the pond might be able to tell us why this place is called ‘Reindeer Island', we believe that this is a rest-stop for Santa Claus during his busy night before Christmas. 117)

- Smaller islands can be seen along the edges of the image, while the swirling shades of green in the waters is an algal bloom. Although algae grows naturally in the lake, high levels of phosphorus – found in fertilizers and common household products – seeping into the water have caused a steady surge of toxic cyanobacteria, or blue–green algae, posing a threat to ecology and human health.

- Sentinel-2's frequent revisits over the same area and high resolution allow changes in inland water bodies and the coastal environment to be closely monitored. With its 13 spectral channels, the mission's novel imager can capture water quality indicators such as the surface concentration of chlorophyll, detect harmful algal blooms and measure water clarity – giving a clear indication of the health and pollution levels.

- By providing measurements of water quality and detecting changes, Sentinel-2 supports the sustainable management of water resources, and can also indicate areas that are safe, or unsafe, for swimming.

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Figure 87: This image of Sentinel-2 of Reindeer Island in Lake Winnipeg was captured on 6 October 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• December 8, 2017: Toulouse is positioned on the banks of the River Garonne, the city is France's fourth largest with a population of 500,000. It is nicknamed the Ville Rose – pink city – owing to the color of the terracotta bricks commonly used in the local architecture. Even from space, the pinkish tint from the terracotta roof tiles is evident as shown with the MSI (Multispectral Imager) on Sentinel-2 in Figure 88. 118)

- In the upper left we can see the runways of the Toulouse-Blagnac airport. The air route to the Paris Orly airport is one of the busiest in Europe.

- Fields blanketing the countryside dominate the image. In fact, France is the EU's leading agricultural power and is home to about a third of all agricultural land within the EU. While agriculture brings benefits for economy and food security, it puts the environment under pressure. Satellites can help to map and monitor land use, and the information they provide can be used to improve agricultural practices.

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Figure 88: Sentinel-2A image of Toulouse in southern France and the surrounding agricultural landscape, acquired on 10 July 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• December 1, 2017: The Copernicus Sentinel-2A satellite takes us over northern Brazil on 22 August 2017, where the Amazon River meets the Atlantic Ocean (Figure 89). The sediment-laden water appears brown as it flows from the lower left to the open ocean in the upper right. ‘Popcorn' clouds are visible in parts of the image – a common occurrence during the Amazon's dry season, formed by condensed water vapor released by plants and trees during the sunny day. 119)

- The land varies in color from the deep green of dense vegetation to light brown. Taking a closer look to the upper-left section of the image, we can see large brown areas where the vegetation has already been cleared away. Geometric shapes indicate agricultural fields, and linear roads cut through the remaining dense vegetation.

- Rainforests worldwide are being destroyed at an alarming rate. This is of great concern because they play an important role in global climate, and are home to a wide variety of plants, animals and insects. More than a third of all species in the world live in the Amazon Rainforest.

- Unlike other forests, rainforests have difficulty of regrowing after they are destroyed and, owing to their composition, their soils are not suitable for long-term agricultural use.

- With their unique view from space, Earth observation satellites have been instrumental in highlighting the vulnerability of the rainforests by documenting the scale of deforestation.

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Figure 89: Sentinel-2A image of the Amazon River emptying into the Atlantic Ocean and of northern Brazil, acquired on 22 August 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• November 17, 2017: From the Salar de Atacama salt flat in the east to the Cordillera Domeyko mountains in the west, Sentinel-2 takes us over part of the Atacama Desert in northern Chile. 120)

- The desert runs along part of South America's central west coast. It is considered one of the driest places on Earth. Being a ‘coastal desert', the cold, upwelling waters in the Pacific Ocean inhibit rain from reaching the land. Instead, the winds that blow from the ocean bring fog.

- Because of the Atacama plateau's high altitude, low cloud cover and lack of light pollution, it is one of the best places in the world to conduct astronomical observations and home to two major observatories.

- Some areas of the desert have been compared to the planet Mars, and have been used as a location for filming scenes set on the red planet. ESA has even tested a self-steering rover in the Atacama, which was selected for its similarities to martian conditions.

- In the lower right of Figure 90, the geometric shapes of large evaporation ponds dominate the Salar de Atacama – Chile's largest salt flat. At about 3,000 km2, it is the world's third largest salt flat as well as one of the largest active sources of lithium. From evaporation ponds like the ones pictured here, lithium bicarbonate is isolated from salt brine. Lithium is used in the manufacturing of batteries, and the increasing demand has significantly increased its value in recent years – especially for the production of electric-car batteries.

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Figure 90: Sentinel-2A image of part of the Atacama Desert in northern Chile, captured on 29 April 2017 (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• November 10, 2017: The Copernicus Sentinel-2B satellite takes us to the Republic of Fiji in the South Pacific Ocean on 28 September 2017. Part of Fiji's largest island, Viti Levu, is pictured here, with coral reefs speckling the water (Figure 91). 121)

- Shaped by volcanic activity and earthquakes, the center of the island is dominated by forests and a mountain range. The highest peak, Mount Tomanivi, reaches over 1320 m and is located on the central-right side of the image. While the area east of the mountain range receives heavy rainfall, the west side pictured here is in the ‘rain shadow', meaning that the mountains block the rain clouds, leaving this area drier than the east.

- In addition to the human population of some 600 000, one of the largest insect species also resides on Viti Levu: the giant Fijian long-horned beetle. The island is the only known home to the beetle, which grows up to about 15 cm long – excluding antennae and legs.

- With more than 300 islands, the Fijian archipelago's low-lying coastal areas are at risk of sea-level rise – a devastating consequence of climate change. Satellites carry special instruments to measure sea-level rise – but not only. Different instruments can measure different climate variables, from greenhouse gases to melting glaciers, and offer a global view of the state of our planet.

- The Republic of Fiji holds the presidency for this year's COP 23 (Conference of the Parties) on climate, held this week and next at the UN Framework Convention on Climate Change headquarters in Bonn, Germany.

- In February 2016, Cyclone Winston struck Fiji, damaging tens of thousands of homes and buildings, leaving more than 130,000 in need of shelter. With the COP 23 Presidency, Fiji calls for everyone to come together to build partnerships for climate action between governments, civil society and the private sector – and to work together to improve the climate resilience of vulnerable nations and communities.

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Figure 91: On 28 Sept. 2017, Sentinel-2 captured part of Fiji's largest island with coral reefs speckling the water (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

• October 3, 2017: From the barren Sahara to lush jungles, the first high-resolution map classifying land cover types on the entire African continent has been released. The map was created using a year's worth of data from the Sentinel-2A satellite. At a resolution of 20 m per pixel, you can now explore African's diverse landscapes from grasslands to croplands, water bodies to deserts. 122)

- Land-cover mapping breaks down the different types of material on Earth's surface. This information is important for understanding changes in land use, modelling climate change extent and impacts, conserving biodiversity and managing natural resources.

- The map released this week comprises 180,000 Sentinel-2A images representing 90 TB captured between December 2015 and December 2016. Considering the size of the map – about six gigabytes – a web interface was developed to visualize the data.

- The map was developed under ESA's CCI (Climate Change Initiative) Land Cover project, and users are invited to provide their feedback on the new map through an online form.

- "The prototype high-resolution land cover map at 20m over Africa is an impressive demonstration of the Sentinel-2A data availability and of the present capabilities for the processing of such huge volumes of data," said Frédéric Achard from the Joint Research Centre. "The community dealing with land resources in Africa will surely look forward with great interest to this prototype and to its future development."

- ESA has been coordinating global land cover maps since 2002 through its GlobCover and CCI Land Cover projects at a resolution of 300 m. While the latest map of Africa is based on observations from one of the twin Sentinel-2 satellites, the launch of Sentinel-2B in March 2017 has put the possibility of a global map at 10 m within reach.

- The pair of Sentinel-2 satellites offer ‘color vision' for Europe's Copernicus program. They each carry a multispectral imager with 13 spectral bands that can be used for agricultural and forestry practices and for helping manage food security. Satellite images can be used to determine various plant indices such as leaf area chlorophyll and water content.

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Figure 92: At 20 m resolution, this land cover classification map of Africa was created using 180,000 Copernicus Sentinel-2A images captured between December 2015 and December 2016 (image credit: ESA, the image contains modified Copernicus Sentinel data (2015-2016), processed by Land Cover CCI, ESA) 123)

• September 29, 2017: The Copernicus Sentinel-2A satellite takes us over the jagged islands along the west coast of Greenland in this false-color image captured on 8 August 2017. Covering more than 2,000,000 km2, Greenland is the world's largest island and home to the second largest ice sheet after Antarctica. But these ice sheets are sensitive to changes in our climate, and rising temperatures are causing them to melt faster. 124)

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Figure 93: The jagged islands along the west coast of Greenland were captured in a Sentinel-2 false-color image on 8 August 2017. On the right side of this image, the Nordenskiold Glacier is just one of many glaciers draining Greenland's ice sheet (image credit: ESA, the image contains modified Copernicus Sentinel data (2017), processed by ESA, CC BY-SA 3.0 IGO)

- Scientists use Earth-observing satellites to track the ice loss. Between 2011 and 2014, Greenland lost around 1000 billion tons of ice. This corresponds to a 0.75 mm contribution to global sea-level rise each year.

- Melting ice sheets caused by rising temperatures and the subsequent rising of sea levels is a devastating consequence of climate change, especially for low-lying coastal areas. In addition, the increased influx of freshwater into oceans affects the salinity, which in turn affects global ocean currents – a major player in the regulation of our climate.

- Vegetation appears red in this false-color image, as the land here is covered by grasses and low-lying plants. Swirls of light blue in the water are suspended fine sediment produced by the abrasion of glaciers rubbing against rock, called ‘glacier milk'.