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• November 30, 2018: The Copernicus Sentinel-1 mission takes us over Mexico City. This huge, densely-populated capital can be seen in the top right of the image. It is home to almost nine million people, with the Greater Mexico City area recording a population of over 21 million. This makes it the largest Spanish-speaking city in the world. ¹⁾

- In the left of the image, three bodies of water are shown in black: Villa Victoria, Valle de Bravo, and Tepetitlán. Water is significant to the development of Mexico City, which is thought to have been built over a lake by the Aztecs around 1325.

- Today, the city finds itself in a precarious situation in terms of water supply in spite of the regular flash floods and heavy rainfall it experiences during the wet season from June and September.

- In the top right, we can see the round structure of El Caracol meaning ‘the snail’ in Spanish. Currently used as a reservoir for industrial facilities within Mexico City, there are plans for this to become a wastewater treatment plant. A 62 km-long sewer tunnel is also due to begin operating this year.

- The Cumbres del Ajusco national park is shown to the southwest of the capital, in an area of the image that shows colorful dots forming a circle. Famous for being up to almost 4000 m above sea level at its highest elevation, it is one of many national parks surrounding the capital.

- Volcanoes are also dotted around this area. Popocatépetl, to the south east of Mexico City, last erupted in September 2018.

• On 8 October 2018 at 05:28 GMT (07:28 CEST), the Copernicus Sentinel-1 mission captured its first images of the oil spill from a collision between two ships that had occurred the day before in the Mediterranean Sea, north of the French island of Corsica. This first image shows that the oil slick was about 20 km long. By the evening at 19:21 CEST, however, imagery shows that the slick had lengthened to about 35 km. And 24 hours later, on 9 October at 19:14 CEST, the slick had grown to about 60 km long. ²⁾

Legend to Figure 2: The image from 9 October also shows a large black patch southeast of the oil slick – this is a result of low reflectivity of the radar signal and therefore depicts calm waters.

• October 8, 2018: The Copernicus Sentinel-1 mission has imaged the oil spill in the Mediterranean following a collision between two merchant ships on Sunday 7 October 2018. A Tunisian cargo ship is reported to have struck the hull of a Cypriot container ship in waters north of the French island of Corsica. There were no casualties, but the collision caused a fuel leak – which has resulted in an oil slick about 20 km long. Although the collision occurred in French waters, the cleanup operation is part of a joint pact between France, Italy and Monaco to address pollution accidents in the Mediterranean. ³⁾

• September 28, 2018: The Copernicus Sentinel-1B satellite takes us over central Italy. From the Apennine Mountains in the top right, to the fertile, former lakebed of the Avezzano plain in the center right, this bright, false-color image (Figure 4) captures the diversity and beauty of the region’s landscapes. ⁴⁾

- Dual-polarization radar technology has been used, resulting in vibrant shades of green for most of the land surface shown. Built-up areas, such as Italy’s capital city of Rome, appear in shades of red and pink. Meanwhile, the structure of the agricultural fields of Altopiano in the Abruzzo region is clearly reflected in a combination of blue and violet hues.

- This radar technology allows us to see the crater lake structures of the volcanic lakes of Nemi and Albano in the bottom left clearly. The same is true for Lago di Vico with the volcano and crater clearly visible in the top left of the image.

- The central region of Italy is an important one for the space industry. For example, ESA’s center for Earth observation, which celebrates its 50-year anniversary this week, is located in this area.

- This region is also prone to earthquakes. In August 2016, a magnitude 6.2 earthquake struck the small towns of Amatrice, Accumoli and Pescara del Tronto. It was followed by two aftershocks. A magnitude 6.6 earthquake in Norcia followed in October the same year. The tremor of this last earthquake was felt across the country. It was the most powerful one to hit Italy since 1980.

• September 14, 2018: The Copernicus Sentinel-1B satellite takes us over Semera in northeast Ethiopia. Semera is a new town with a population of just over 2600 and serves as the capital of the Afar region. The region spans an estimated 270,000 km², from close to the border with Eritrea towards the capital of Addis Ababa (also written as Addis Abeba). ⁵⁾

- We can see the regional capital in the top right of this false-color image (Figure 5), with the larger urban center of Dubti just south of the town. Both are found in the Great Rift Valley, which lies between the Ethiopian Plateau and the Somalia Plateau.

- The landscape of the Afar region is characterized by desert shrubland and volcanoes, particularly in the north. In this image we can see differences in altitude represented in the variations in color. The left part of the image is dominated by yellow, signifying changes in vegetation found at higher altitudes. Two lakes, Hayk Lake and Hardibo Lake, are shown in the bottom left.

- South of Dubti we can see the Awash River, which flows into the northern salt lakes rather than into the sea. Salt trade is typical of the area, whilst cotton is grown in the Awash River valley. Maize, beans, papaya and bananas are also cultivated in the Afar region. It is thought that 90% of the region’s population lead a pastoral life, rearing animals such as camels, sheep and donkeys.

- Dallol, to the north of Semera in Ethiopia’s Danakil Depression, is frequently cited as one of the hottest inhabited places on Earth. Lying 125 m below sea level, with temperatures in the spectacular hydrothermal fields averaging 34.4 °C year-round, and the area receiving just 100–200 mm rainfall a year, conditions are thought to be amongst the most inhospitable in the world.

• September 13, 2018: In July 2017, one of the largest icebergs on record calved from the Larsen C ice shelf in Antarctica. However, sea ice to the east and shallow waters to the north kept this giant berg, named A68, hemmed in. So for more than a year it wafted to and fro, but never left its parent ice shelf’s side. Strong winds blowing from Larsen C have finally given it the push it was waiting for. In early September 2018, these winds pushed the southern end of the berg out into the Weddell Gyre. This clockwise drift of ocean waters and sea ice flowing north past the Larsen shelf, which can be seen in the animation as a flow from right to left, has rotated A68 out into the Weddell Sea. Here it is freer to float away and be carried further north into warmer waters. ⁷⁾

• August 8, 2018: Scientists with the ARIA (Advanced Rapid Imaging and Analysis) project , a collaboration between NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, used synthetic aperture radar (SAR) data from the European Union's Copernicus Sentinel-1A and -1B satellites, operated by the European Space Agency. They generated a map of the deformation of Earth's surface caused by the Aug. 5, 2018 magnitude 6.9 earthquake under Lombok island, Indonesia (Figure 7). The deformation map is produced from automated interferometric processing of the SAR data using the JPL-Caltech ARIA data system in response to a signal received from the U.S. Geological Survey. The false-color map shows the amount of permanent surface movement that occurred almost entirely due to the quake, as viewed by the satellite, during a 6-day interval between two Sentinel-1 images acquired on July 30 and Aug. 5, 2018. ⁸⁾

- From the pattern of deformation in the map, scientists have determined that the earthquake fault slip was on a fault beneath the northwestern part of Lombok Island and caused as much as 25 cm of uplift of the ground surface. The map depicts motion towards the satellite (up and west) in the direction of the radar's line-of-sight, with contours every 5 cm. White areas are places where the radar measurement was not possible, largely due to dense forests in the middle of the islands.

• July 30, 2018: Copernicus Sentinel-1 data are highlighting the collapse of the Xe-Pian Xe-Namnoy dam in the southeastern province of Attapeu in Laos. The collapse has led to flash floods that have claimed several lives and left many more people missing, according to local news reports. ⁹⁾

- Sentinel-1’s radar ability to ‘see’ through clouds and rain, and in darkness, makes it particularly useful for monitoring floods. Images acquired before and after flooding offer immediate information on the extent of inundation and support assessments of property and environmental damage.

- The C-band synthetic aperture radar on Sentinel-1 can provide large swath images with a resolution of 20 m and within hours of acquisition to aid emergency response. — With construction starting back in 2013, the dam had been expected to commence commercial operations this year.

- The flood seems to have been caused by a breach in another saddle dam (not the main dam) following heavy rainfall. The effects of this can be seen clearly at larger scale, with the flood following the Vang Ngao river down to the villages. This is shown in the animation here.

- The catastrophe triggered the International Charter Space and Major Disasters. With 16 members, the Charter takes advantage of observations from several satellites, providing a unified system of space data acquisition and delivery to support disaster management.

- With the ability to mobilize agencies around the world through a single access point that operates 24 hours a day, 7 days a week, the Charter helps civil protection authorities and the international humanitarian community in the face of major emergencies.

- By supplying reliable and accurate information, these entities are better equipped to save lives and limit damage to property, infrastructure and the environment.

- Since its first activation in 2000, the Charter has called on space assets on hundreds of occasions, helping respond to disasters such as floods, hurricanes, tsunamis and earthquakes.

• July 13, 2018: The Copernicus Sentinel-1 mission has revealed that, on average, Greenland’s glaciers are now flowing more slowly into the Arctic Ocean. While glacial flow may have slowed overall, in summer glaciers flow 25% faster than they do in the winter. ¹¹⁾

- While the general flow has reduced in recent years, during the summer it speeds up, with glaciers flowing up to 25% faster than in the winter.

- A paper published recently in The Cryosphere details the research led by the UK’s CPOM (Centre for Polar Observation and Modelling) where the Copernicus Sentinel-1 mission was used to track Greenland’s four main glaciers: Jakobshavn Isbrae, Petermann, Nioghalvfjerdsfjorden and Zachariae Isstrom between 2014 and 2017. ¹²⁾

- We all know that ice melts pretty quickly under the summer sun, but monitoring exactly how glacial flow changes according to the season is important for understanding glacial dynamics. In turn, this is vital to assess the risk of sea-level rise, which is a major concern around the world.

- Together, these four glaciers contain enough water to raise global sea levels by 1.8 m.

- Adriano Lemos from CPOM noted, “Sentinel-1 has real advantages for studying glaciers. We now get more data and more often so we can see the finer detail in even the most inaccessible and fast-moving areas.”

- Part of European Union’s fleet of Copernicus missions, Sentinel-1 is a two-satellite constellation that images the entire Earth every six days – important for monitoring rapid change. Each satellite carries an advanced radar instrument that can image Earth’s surface through cloud and rain and regardless of whether it is day or night.

- This is essential for monitoring the polar regions, which are shrouded in darkness during the long winter months.

- “We saw this summer speed-up at all four glaciers and it is important that we continue to monitor this speed throughout the year to fully understand how the glaciers are moving” explained Adriano Lemos.

- Anna Hogg also from CPOM added, “Acquiring all this valuable radar data needed international coordination between multiple space agencies such as ESA and the German Aerospace Center DLR. This paper shows how our efforts are being rewarded through improving our understanding of environmental change in Greenland.”

• June 2018: The Sentinel-1 mission has set a benchmark for achieving a high-quality end-to-end SAR performance, showing almost identical radiometric and geolocation accuracy for Sentinel-1A &-1B. ¹⁴⁾

- In addition, the 6-day repeat orbit interval along with small orbital baselines enables the implementation of cross-InSAR by combining data acquired by Sentinel-1A&-1B from repeat-pass orbits, reducing significantly the temporal surface decorrelation effect. This supports geophysical applications, such as the monitoring of cryosphere dynamics and the mapping of surface deformation.

- The continuous and systematic Sentinel-1 SAR and InSAR data acquisition, while providing an instantaneous wide area coverage, enables the build-up of long data time series. This has triggered a shift from individual image analysis to time-series processing.

• May 29, 2018: In what the UN describes as the world’s fastest growing refugee crisis, almost 700,000 Rohingya Muslims have fled Myanmar for neighboring Bangladesh since August 2017. With the Bangladesh government proposing a vulnerable low-lying island as a relocation site for thousands, Sentinel-1 data have shown how unsuitable this site would be. ¹⁵⁾

- While the Rohingya have faced decades of repression, this recent mass exodus is blamed on large-scale atrocities committed by the Myanmar military. - Not only has the pace of arrivals in Bangladesh made this the fastest growing refugee crisis in the world, but the concentration of displaced people now in Bangladesh’s Cox’s Bazar is amongst the densest in the world. Even before the crisis, Bangladesh was hosting more than 200,000 Rohingya from Myanmar. For a country already struggling to cope with challenges of its own, this has turned into a huge humanitarian tragedy.

- Desperate to find solutions, the Bangladesh government was prompted, unsurprisingly, to revive a much criticized plan to move thousands to Thengar Char, one of several uninhabited and unstable islands in the Bay of Bengal.

- The area is particularly prone to cyclones, with coastal zones and islands at highest risk. Some nearby islands have a tidal range as high as 6 m, meaning that they are at risk of being completely submerged. - Regardless of cyclones, the region is often inundated by heavy rainfall during the South Asian monsoon, which lasts from June to October.

- Information from satellites is often used during humanitarian crises to map, for example, the extent of camps and other temporary settlements. In this case, however, the Earth Observation-based Services for Dynamic Information Needs in Humanitarian Action project used data from the Copernicus Sentinel-1 radar mission to show exactly how precarious Thengar Char is.

- Andreas Braun from Germany’s University of Tübingen said, “As well as using data from Sentinel-1, we also used data from ESA’s old ERS and Envisat satellites to work out how the size of the island has changed since 1991 (Figure 12).

- “It turns out that this set of islands has only been there since 2009, and were formed from silt washing down from the Himalayas into the Bay of Bengal. We calculated how big the island has ever been, how small it has ever been and how big it is on average. Importantly, we could report that since Sentinel-1 became operational in 2014, the island, which is currently about 60 km², has been inundated several times and at the worst, the land area was reduced to 39 km².”

- The notion of placing vulnerable people on an inhospitable island that has no existing infrastructure and is two hours away by boat from the mainland is obviously questionable, but thanks to Sentinel-1, the authorities have hard evidence as to its risk of flooding.

- It remains to be seen whether the government of Bangladesh will move forward with their plan, although construction work has apparently begun.

• Mission status 22-28 May, 2018: The Sentinel-1 Yearly Mission Review took place on 24 May 2018, at ESA-ESRIN. The overall mission is in a very good shape, and both satellites demonstrate a good health. The occurrence of satellite anomalies and mission unavailability periods has further decreased over the past months. A major increase of the Sentinel-1 operations capacity has been achieved during the past year with the smooth integration of the EDRS service in operations, and a series of improvements were performed (e.g. systematic production of L2 OCN (Level 2 Ocean) products from IW/EW/SM modes). Substantial improvements on the data quality have been achieved (e.g. provision of de-noising information), and will be pursued. Remaining system issues are being addressed, in particular the Level 2 OCN RVL product qualification. The Copernicus operational services have expressed satisfaction on the routine use of Sentinel-1 data. Data and user access statistics, as well as the numerous exploitation activities based on Sentinel-1 data, confirm the great user uptake in various thematic application and scientific fields. ^{17) 18)}

- The Sentinel-1A and Sentinel-1B routine operations are on-going

- The Sentinel-1 observation scenario supports the systematic coverage of Copernicus Services areas of interest, of European land and coastal waters, of global tectonic/volcanic areas, as well as of other areas worldwide for various applications. The observation plan also includes a regular mapping of all land areas worldwide.

- World maps providing a high level description of the Sentinel-1 constellation observation scenario, in terms of SAR modes, polarization, observation geometry, revisit and coverage frequency are available at: https://web.archive.org/web/20210728083602/https://sentinels.copernicus.eu/web/sentinel/missions/sentinel-1/observation-scenario

- The detailed observation plan in the form of instrument acquisition segments, for both Sentinel-1A and Sentinel-1B is published at: https://sentinels.copernicus.eu/web/sentinel/missions/sentinel-1/observation-scenario/acquisition-segments

- The operational use of Sentinel-1 data by the Copernicus Marine Environment Monitoring Service (CMEMS) for sea-ice and iceberg monitoring activities is on-going.

- The European Maritime Safety Agency (EMSA) operationally uses Sentinel-1 imagery in quasi-real time in the CleanSeaNet services; operations with EMSA service providers local stations are on-going.

- Specific planning was made to support the activation EMSR286 from the Copernicus Emergency Management Service related to monitoring the risk of failure of the Ituango dam in Colombia.

- Specific actions (fast delivery of already planned acquisitions) were implemented to support the activation EMSR287 from CEMS related to floods in Saxony, Germany.

- Both Sentinel-1A and -1B spacecraft are in a stable state, operating in Nominal Mission Mode (NMM). The Flight Operations Segment (FOS) ensuring the monitoring, control and commanding of the satellites is operating nominally. Orbit control maneuvers are performed once a week.

- The use of the EDRS-A service by Sentinel-1A and -1B is on-going as part of the routine operations.

- X-Band data acquisitions are routinely performed over Matera, Svalbard and Maspalomas X-band core stations. The acquired data are circulated within the Payload Data Ground Segment (PDGS), systematically processed to Level-0 and Level-1 products and archived.

- Wave Mode data are regularly acquired over open oceans, systematically processed to Level-2 OCN products and made available. Sentinel-1 IW and EW Level-2 OCN products over regional ocean areas are available on the Data Hubs. The operational qualification of the Level-2 the OCN Radial Surface Velocity (RVL) component is on-going.

- Operations are performed regularly at the Processing and Archiving Centres (DLR-PAC and UK-PAC). All other PDGS operational services (i.e. Mission Performance, Precise Orbit Determination, Wide Area Network) are operating nominally.

- By 24^th May 2018, a total of 153,443 users have self-registered on the Sentinels Scientific Data Hub; 14.6 million Sentinel-1 product downloads have been made by users, corresponding to 19 PB of data. 2.6 million Sentinel-1 products are available on-line for download, representing about 4 PB of data. Statistics of last 24 hours are available in real time at the Open Data Hub home page: https://scihub.copernicus.eu

• March 22, 2018: Two giant sinkholes near Wink, Texas, may just be the tip of the iceberg, according to a new study that found alarming rates of new ground movement extending far beyond the infamous sinkholes. That's the finding of a geophysical team from SMU (Southern Methodist University), Dallas that previously reported the rapid rate at which the sinkholes are expanding and new ones forming. - Now the team has discovered that various locations in large portions of four Texas counties are also sinking and uplifting. ¹⁹⁾

- Radar satellite images show significant movement of the ground across a 4000-square-mile area (10 ,360 km²) - in one place as much as 1 m over the past two-and-a-half years, say the geophysicists.

- The West Texas’ Permian Basin, consisting of ancient marine rocks, is underlain by water-soluble rocks and multiple oil-rich formations. In the region that is densely populated with oil producing facilities, many localized geohazards, such as ground subsidence and micro-earthquakes, have gone unnoticed. Here we identify the localized geohazards in West Texas, using the satellite radar interferometry from newly launched radar satellites (Sentinel-1A/1B) that provide radar images freely to public for the first time, and probe the causal mechanisms of ground deformation, encompassing oil/gas production activities and subsurface geological characteristics. Based on our observations and analyses, human activities of fluid (saltwater, CO₂) injection for stimulation of hydrocarbon production, salt dissolution in abandoned oil facilities, and hydrocarbon extraction each have negative impacts on the ground surface and infrastructures, including possible induced seismicity. Proactive continuous and detailed monitoring of ground deformation from space over the currently operating and the previously operated oil/gas production facilities, as demonstrated by this research, is essential to securing the safety of humanity, preserving property, and sustaining the growth of the hydrocarbon production industry. ²⁰⁾

- Geohazards pose a severe threat to humanity, civilian properties, infrastructures, and industries, possibly leading to the loss of life and high economic values. Monitoring areas prone to geohazards is invaluable for locating their precursory signals on the surface, alerting civilians to potential disasters, mitigating the catastrophic outcomes, and facilitating the decision-making processes on the construction and operation of infrastructures and industrial facilities. The United States mid-continent has long been considered geologically stable with no large scale tectonic movements, volcanism, or seismic activities. Therefore, unlike California with its dense GPS networks and frequent survey (aerial, spaceborne, field) campaigns, the mid-continent has garnered less attention from scientific communities and federal/state governments. However, recent studies have revealed that some of the mid-continent, especially the Gulf Coast of the United States including Texas, Louisiana, and Mississippi, is not immune to large-scale and/or localized geohazards.

- The geohazards along the southern United States have been both naturally induced and stimulated by human activities. Besides the occasional, strong tropical storms and flooding in lowlands, natural geohazards include settlement due to sediment loading and glacial isostatic adjustment, which can make the coastline in the Gulf Coast vulnerable to sea-level changes. However, the naturally occurring surface subsidence on the coast displays characteristics of a continuous, slow progression (mm/year) and a large spatial extent (~100 km wide). In contrast, human-induced geohazards are faster growing (up to tens of cm/year) and encompass a varying but generally small area (up to a couple of km wide). The most prominent difference between natural and human-induced geohazards is the correlation between surface instability and anthropogenic activities (e.g., mining, groundwater extraction, hydrocarbon production). Although there can be a time delay of ground deformation after human activities, depending on the geological characteristics (porosity, elasticity, compressibility, pore pressure, permeability) of soils and rocks and types of the operations, human-induced surface subsidence or uplift usually has high proximal and temporal correlation with those activities.

- West Texas is somewhat distant from the Gulf coast, but was inundated by relatively shallow seas during the early part of the Paleozoic Era (approximately 600 to 350 million years ago). The sediments formed during this period contributed to the accumulation of sandstone, shale, and limestone. The seas constituting broad marine environments in West Texas gradually withdrew, and by the Permian Period (approximately 299 to 251 million years ago), thick evaporites (salt, gypsum) accumulated in a hot arid land encompassing shallow basins and wide tidal flats. As a consequence of geological formation in West Texas, the deposited carbonate (reef limestone) and marine evaporite sequences played an important role in the formation of oil reservoirs by helping seal the traps and preserving the hydrocarbons. This resulted in the Permian Basin of West Texas’ massive hydrocarbon reservoirs that became so lucrative to the oil and gas industry.

- In West Texas, human activities such as groundwater exploitation, fluid injection, and hydrocarbon extraction have resulted in surface instability, leading to geohazards such as surface heave/subsidence, fault reactivation, induced seismicity, and sinkhole formation. The vastness of West Texas challenges our ability to identify and locate the relatively small spatial scale of the deformation corresponding to human activities, particularly for fluctuations over the course of a month or a year. Without concerted focus, the small-sized signal in a short time window can go easily undetected. There have been a few studies documenting the surge of surface uplift/subsidence, sinkhole formations, and induced seismicity in oil fields. However, the role of human activities on the surface and subsurface deformation has yet to be fully established, particularly regarding the identification of small-scale deformation signals over a vast region from big datasets spanning multiple years and analyzing them with supplementary information.

- Challenges to the effective study of the geohazards in West Texas include: identification of their locations in remote and vast regions, measurement of their long-term evolution, and characterization of the causal mechanism with accessible information. Satellite radar interferometry (InSAR) has proven capable of imaging ground surface deformation with a measurement accuracy of centimeters or better at a spatial resolution of meters or better over a large region covering tens of thousands km². However, satellite radar acquisitions over West Texas have previously been scarce. Here we present the analysis of the ongoing ground deformations induced by various geohazards around Pecos, Monahans, Wink, and Kermit in West Texas (Figure 13), using multi-temporal InSAR observations based on radar imagery from the first free, open-source radar satellites Sentinel-1A/B.

- The objective of our study is to probe the association between the ongoing localized geohazards in West Texas and anthropogenic activities. To achieve the goal, we focus on the localized, small-sized (200 m~2 km wide), and rapidly developing (cm/yr) geohazards in the region, which are categorized based on six possible causes: i) wastewater injection, ii) CO₂ injection for enhanced oil recovery (EOR), iii) salt/limestone dissolution, iv) freshwater impoundment in abandoned wells, v) sinkhole formation in salt beds, and vi) hydrocarbon production. In addition, time-series measurements from two different imaging geometries are integrated to decipher the deformation phenomena. Furthermore, through comparative analysis of records of fluid injection, hydrocarbon production, and geological characteristics, we establish the relationship between the possible causes of human activities or natural perturbation and the localized observed geohazards in West Texas.

• February 23, 2018: The Copernicus Sentinel-1 mission takes us over the Bering Strait (Figure 14), which connects the Pacific and Arctic Oceans between Russia (Siberia) and the US state of Alaska. ²¹⁾

- Since the Bering Strait lies slightly south of the polar circle, days are short during the winter. Thanks to its radar, Sentinel-1 can ‘see’ through clouds and in the dark, making it especially valuable for monitoring parts of the planet that endure relatively dark winter months. Offering this ‘radar vision’, images from Sentinel-1 can be used for charting icebergs and for generating maps of sea ice for year-round navigation.

- Additionally, monitoring changes in the extent of sea ice is critical for understanding the effect of climate change on our environment.

- It has been reported that sea ice in the Bering Strait has been particularly low this winter. This is because unusually warm water streamed up from the south, causing some of the sea ice to melt earlier than usual. As a result, areas that would have remained covered with reflective sea ice were open for much longer. The relatively dark surface of the sea was able to absorb a lot of energy from the Sun, which prevented sea ice forming in the autumn. Also, recent storms have helped to break up much of the sea ice that did manage to form.

• December 15, 2017: The Sentinel-1 radar satellite mission takes us over Orange County and surrounding areas in the US state of California. ²²⁾

- Two prominent geological features are visible in Figure 15: the coastal plains of the Los Angeles Basin in the upper-central left, and the Santa Ana Mountains running from the upper left to the lower right.

- A typical feature of Pacific Coast mountain ranges like Santa Ana is a moister western slope and drier eastern slope – reflected in this radar image by the more prominent colors on the left side of the mountain range. This is due to air masses from the Pacific bringing precipitation to the land, while the mountains force the clouds to rise and produce rain and block them from moving further east, causing a ‘rain shadow’ and thus drier areas on the other side.

- To respond to dry conditions in California and all over the world, populations rely on dams and reservoirs to control the water supply. In satellite imagery, these water bodies are easy to identify by the straight-cut line of the dam blocking water flow – two of which are visible in the center-right part of the image.

Legend to Figure 15: One obvious example of changes can be seen in the boats in the water on the left side of the image, appearing in the three different colors depending on when they were present. - In other parts of the image we can see colors in agricultural fields showing changes in vegetation between the acquisitions.

• November 24, 2017: The Copernicus Sentinel-1 mission gives us ‘radar vision’ over part of Antarctica’s third-largest island, Thurston Island. The satellite’s radar can ‘see’ through clouds and in the dark, making it a valuable tool for monitoring polar regions which are prone to bad weather and long periods of darkness – such as Antarctica. ²³⁾

- The image of Figure 16 combined three passes by Sentinel-1’s radar in March, April and May 2017. Each was assigned a color – red, green and blue – and when merged, changes between the acquisitions appear in various colors.

- The ice-covered island appears grey, showing no change over the three-month period. But changes in sea ice in the upper part of the image appear as speckles of green, red and blue. In the lower part of the image we can see part of the Abbot Ice Shelf appearing in light blue.

- Antarctica is surrounded by ice shelves, which are thick bands of ice that extend from the ice sheet and float on the coastal waters. They play an important role in buttressing the ice sheet on land, effectively slowing the sheet’s flow as it creeps seaward.

- The ice sheet that covers Antarctica is, by its very nature, dynamic and constantly on the move. Recently, however, there has been a worrying number of reports about its floating shelves thinning and even collapsing, allowing the grounded ice inland to flow faster to the ocean and add to sea-level rise.

• November 7, 2017: In late August, the 60 m-long US Coast Guard Cutter Maple completed its navigation through the Arctic’s ice-ridden Northwest Passage (Figure 17). While this was not the first time ships had taken this route, it was the first time that the IIP (International Ice Patrol) had provided iceberg information based exclusively on satellite imagery. — Established in 1914 in response to the sinking of the Titanic, the US Coast Guard IIP monitors iceberg danger in the North Atlantic Ocean for shipping safety. ²⁴⁾

- When the Maple departed from Alaska in mid-July en route through the Arctic to Maryland, USA, the IIP was on guard to assist the crew to navigate through the notoriously icy waters.

- The IIP used data from the Copernicus Sentinel-1 satellite mission, among others, to create charts showing the risk of encountering icebergs after exiting from the Northwest Passage and during transit through the Baffin Bay, Davis Strait and Labrador Sea.

- Sentinel-1 is equipped with radar that can detect icebergs through cloud cover, a capability particularly beneficial in the IIP’s operating area. Sentinel-1 can also distinguish between the thinner, more navigable first-year ice and the hazardous, much thicker multiyear ice to help assure safe year-round navigation in ice-covered Arctic and sub-Arctic zones. These radar images are particularly suited to generating high-resolution ice charts, monitoring icebergs and forecasting ice conditions.

- Scientists at the IIP used iceberg detection software available on ESA’s online Polar TEP (Thematic Exploitation Platform) to access satellite data to detect icebergs and analyze their densities and trajectories.

- “This experience using the Polar TEP cloud-based technology opens the door for future evaluations of a more robust version of the iceberg detection and iceberg trajectory processors,” said Michael Hicks, Chief Scientist of the International Ice Patrol. “Cloud-based technology such as that used by Polar TEP is expected to be an important tool for handling the ever-growing amount of data coming from space.”

- Polar TEP is one of six Thematic Exploitation Platforms developed by ESA to serve data user communities. These cloud-based platforms provide an online environment to access information, processing tools and computing resources for collaboration. TEPs allow knowledge to be extracted from large environmental datasets produced through Europe's Copernicus program and other Earth observation satellites.

• October 31, 2017: In this image from the Copernicus Sentinel-1 satellite mission, we can see the location of the ‘Halloween crack’ on Antarctica’s Brunt Ice Shelf, highlighted in red. The former and current locations of the British Antarctic Survey’s Halley research stations are also marked. ²⁵⁾

- Discovered on 31 October 2016, the swiftly lengthening Halloween crack prompted the temporary withdrawal of staff from the Halley VI research station for the duration of the 2017 Antarctic winter. Information from the Copernicus Sentinel-1 and Sentinel-2 satellites helped in making this decision.

- The base had already been moved 23 km inland during last Antarctica’s summer months because another ice chasm (highlighted in red) had begun to show signs of growth.

- In this image of Figure 20, Sentinel-1’s radar was also able to pick up lines in the snow and ice marking the researchers’ routes from the former location of the Halley VI station to the coast and to the Halloween crack. To help us identify them, these lines have been colored in black.

• October 25, 2017: This year’s Atlantic hurricane season has been a harsh reminder of the grief and devastation brought by these vast storms. Imaging the top of hurricanes from space is nothing new, but the Sentinel-1 satellites can see right through these towering spinning weather systems, measuring the sea surface below to help predict the storm’s path. ²⁶⁾

- The 2017 hurricane season isn’t even over yet, but 10 Atlantic storms in a row have already reached hurricane strength – the first time this has happened in more than a century.

- Since understanding and predicting these powerful weather systems is essential to saving lives and property, scientists have been looking into how the Copernicus Sentinel-1 radar mission can help.

- Information from this state-of-the art mission is used for numerous applications, from monitoring sea ice and marine oil spills to mapping floods and land-surface deformation caused by earthquakes.

- Observing hurricanes wasn’t part of its original remit. Unlike satellites that carry optical instruments, from which we get the familiar images of the top of hurricanes, radar can penetrate clouds to image the sea underneath these powerful and destructive weather systems.

- Taking Sentinel-1 beyond its original scope, scientists at DLR (German Aerospace Center) have developed a technique that allows the radar to probe sea-surface wind and wave heights. - Importantly, this information about the state of the sea can help to assess how destructive a hurricane is and predict its path – and, therefore, where and when it is likely to make landfall. The same information can also be used to warn ships and to issue warnings of coastal flooding.

- This new technique was used for the first time when hurricane Irma struck Cuba and the Florida Keys in early September. Here, waves up to 10 m high were measured.

- Sentinel-1 works in several different operational modes, but it is its ‘wide swath mode’, which is 250 km wide with a resolution of 5 x 20 m, is particularly valuable for understanding ocean waves. This is especially important because in situ measurements of wind and sea state cannot be gained from buoys or dropped probes in such extreme weather or over such a wide area.

- ESA’s Sentinel-1 project manager, Ramón Torres, said, “We see the Sentinel-1 mission being used for many different applications that benefit society, but this is a particularly good example of how the mission could make a real difference to people’s lives. Sentinel-1 is delivering beyond our expectations.”

• October 20, 2017: The Copernicus Sentinel-1A satellite brings us over part of the Sagaing Division in northwest Myanmar (formerly Burma), and along the border with India. ²⁷⁾

- Snaking through the image of Figure 23 is the Chindwin River, which breached its banks during a period of severe flooding in 2015. Monsoon rains beginning that July caused multiple rivers in the region to overflow, causing widespread damage and affecting up to a million people.

- The image was created using two passes by Sentinel-1’s radar. This information was then released in the form of a map under the International Charter Space and Major Disasters to assist relief efforts.

- Currently led by ESA, the Charter is an international collaboration between 16 owners or operators of Earth observation missions. It provides rapid access to satellite data to help disaster management authorities in the event of a natural or man-made disaster.

- Sentinel-1’s radar ability to ‘see’ through clouds, rain and in darkness makes it particularly useful for monitoring floods.

• September 28, 2017: A NASA-produced map showing areas of eastern Puerto Rico that were likely damaged by Hurricane Maria has been provided to responding agencies, including FEMA (Federal Emergency Management Agency). The hurricane, a Category 4 storm at landfall on Puerto Rico on Sept. 20, caused widespread damage and numerous casualties on the Caribbean island, an unincorporated U.S. territory with a population of about 3.4 million. ²⁸⁾

- To assist in disaster response efforts, scientists at NASA's Jet Propulsion Laboratory and Caltech, both in Pasadena, California, obtained and used before-and-after interferometric synthetic aperture radar (InSAR) satellite imagery of areas of Eastern Puerto Rico to identify the areas that are likely damaged. The imagery — acquired before the storm on March 25, 2017 and again one day after landfall on Sept. 21, 2017 — is from the radar instruments on the Copernicus Sentinel-1 satellites operated by the European Space Agency.

- The views indicate the extent of likely damage caused by the hurricane, based on changes to the ground surface detected by radar. The color variations from yellow to red indicate increasingly more significant ground and building surface change. The map is used as guidance to identify potentially damaged areas and may be less reliable over vegetated and flooded areas.

- The radar data were processed by the ARIA (Advanced Rapid Imaging and Analysis) team at JPL and Caltech. ARIA is a NASA-funded project that is building an automated system for demonstrating the ability to rapidly and reliably provide GPS and radar satellite data to support local, national and international hazard-monitoring and response communities. InSAR can "see" through clouds and is sensitive to changes in the roughness of the ground or building surfaces.

- Using space-based radar imagery of disasters, ARIA data products can aid responders in making rapid assessments of the geographic region affected by a disaster, as well as detailed imaging of locations where damage occurred.

Legend to Figure 24: The map is derived from SAR (Synthetic Aperture Radar) images from the Copernicus Sentinel-1A and Sentinel-1B satellites, operated by the ESA. The images were taken before (March 25, 2017) and after (Sept. 21, 2017) the storm's landfall. The map was delivered to responding agencies, including FEMA (Federal Emergency Management Agency), on Sept. 22, 2017. FEMA combined the map with building infrastructure data to estimate a damage density map, which was sent to its Urban Search and Rescue teams in the field in Puerto Rico. ²⁹⁾

The map covers an area of 169 x 96 km, shown by the large red polygon in the figure. The inset, denoted by the orange rectangle, shows the extent of damage in and around the capital city of San Juan. Each pixel measures about 30 m across. The color variation from yellow to red indicates increasingly more significant ground surface change. Preliminary validation was done by comparing the map with anecdotal reports of damage. This damage proxy map should be used as guidance to identify damaged areas, and may be less reliable over vegetated and flooded areas. Sentinel-1 data were accessed through the Copernicus Open Access Hub. The image contains modified Copernicus Sentinel data (2017), processed by ESA and analyzed by the NASA-JPL/Caltech ARIA team. This research was carried out at JPL under a contract with NASA.

• September 20, 2017: Witnessed by the Copernicus Sentinel-1 mission on 12 July 2017, a lump of ice more than twice the size of Luxembourg broke off the Larsen C ice shelf, spawning one of the largest icebergs on record and changing the outline of the Antarctic Peninsula forever. Over the following two months, systematic observations from Sentinel-1 showed that the A68 berg remained close, buffeting back and forth against the ice shelf. It was unclear what would happen to the berg because they can remain in one place for years. ³⁰⁾

- However, the mission has revealed that A68 is now on the move and drifting out to sea. Images from 16 September show that there is a gap of about 18 km as the berg appears to be turning away from the shelf.

• August 17, 2017: For the first time in India, a state government is using satellites to assess lost crops so that farmers can benefit from speedy insurance payouts. — The southern Indian state of Tamil Nadu is home to around 68 million people, of which almost a million are rice farmers. However, Tamil Nadu is facing the worst drought in 140 years, leading to the land being too dry for paddy fields, lost yield, widespread misery and unrest. ³¹⁾

- The Copernicus Sentinel-1 radar mission has been used to alleviate a little of the suffering by providing evidence of damaged land and failed crops so that the Agricultural Insurance Company of India can compensate farmers as quickly as possible. So far, more than 200 000 farmers have received payouts.

- Malay Kumar Poddar, the company’s general manager, said, “Assessing damages based on remote-sensing technology is introducing much objectivity into the crop insurance program. “Beyond the area loss assessment, we are also keen to apply the technology to assess actual yields at the end of the season.”

- Satellites carrying optical cameras can provide images of Earth’s surface only in daylight and in the absence of cloud, but the Sentinel-1 satellites carry radar which works regardless. This makes it an ideal mission to use in tropical and subtropical regions, which are often cloudy.

- Sentinel-1 radar imagery combined with rice-yield modelling is at the heart of the German–Swiss RIICE (Remote-Sensing based Information and Insurance for Crops in Emerging Economies initiative). — Francesco Holecz, from sarmap, set up the service in collaboration with the International Rice Research Institute, RIICE partners, Indian authorities and universities. He said, “The reliable repetitiveness of the Sentinels, their short revisit intervals, the free, quick and easy access to the products and the high quality of the data have contributed a lot to the practicability of satellite-based rice monitoring systems.”

- Gagandeep Singh Bedi, agricultural production commissioner and principle secretary to the government in Tamil Nadu added, “RIICE remote-sensing technology allows us to assess crop loss and damages in a more transparent and timely manner. “It was particularly useful during the last cropping season to identify villages that had been hit by drought, and farmers benefited from the technology by getting claims in a record time.”

- The research network is also working with partners in other countries to develop the method further. For example, the Tamil Nadu Agricultural University and the International Rice Research Institute in the Philippines are looking to use it to assess yields at the end of the season. Sellaperumal Pazhanivelan, from the university, said, “We believe that this technology can help the state governments to obtain objective and transparent data on actual rice yields so that farmers affected by natural hazards can be identified quickly.”

• July 12, 2017: Over the last few months, a chunk of Antarctica’s Larsen C ice shelf has been hanging on precariously as a deep crack cut across the ice. Witnessed by the Copernicus Sentinel-1mission, a lump of ice more than twice the size of Luxembourg has now broken off, spawning one of the largest icebergs on record and changing the outline of the Antarctic Peninsula forever. ³²⁾

- The fissure first appeared several years ago, but seemed relatively stable until January 2016, when it began to lengthen.

- In January 2017 alone it travelled 20 km, reaching a total length of about 175 km.

- After a few weeks of calm, the rift propagated a further 16 km at the end of May, and then extended further at the end of June.

- More importantly, as the crack grew, it branched off towards the edge of the shelf, whereas before it had been running parallel to the Weddell Sea. With just a few km between the end of the fissure and the ocean by early July, the fate of the shelf was sealed.

- Scientists from Project MIDAS, an Antarctic research consortium led by Swansea University in the UK, used radar images from the Copernicus Sentinel-1 mission to keep a close eye on the rapidly changing situation.

- Since Antarctica is heading into the dark winter months, radar images are indispensable because, apart from the region being remote, radar continues to deliver images regardless of the dark and bad weather.

- Adrian Luckman, leading MIDAS, said, “The recent development in satellite systems like Sentinel-1 has vastly improved our ability to monitor events such as this.”

- Noel Gourmelen from the University of Edinburgh added. “We have been using information from ESA’s CryoSat-2 mission, which carries a radar altimeter to measure the surface height and thickness of the ice, to reveal that the crack was several tens of meters deep.”

- As predicted, a section of Larsen C – about 6000 km² – finally broke away as part of the natural cycle of iceberg calving. The behemoth iceberg weighs more than a million million tons and contains about the same amount of water as Lake Ontario in North America.

- “We have been expecting this for months, but the rapidity of the final rift advance was still a bit of a surprise. We will continue to monitor both the impact of this calving event on the Larsen C ice shelf, and the fate of this huge iceberg,” added Prof. Luckman.

- The iceberg’s progress is difficult to predict. It may remain in the area for decades, but if it breaks up, parts may drift north into warmer waters. Since the ice shelf is already floating, this giant iceberg does not influence sea level.

- With the calving of the iceberg, about 10% of the area of the ice shelf has been removed.

- The loss of such a large piece is of interest because ice shelves along the peninsula play an important role in ‘buttressing’ glaciers that feed ice seaward, effectively slowing their flow.

- Previous events further north on the Larsen A and B shelves, captured by ESA’s ERS and Envisat satellites, indicate that when a large portion of an ice shelf is lost, the flow of glaciers behind can accelerate, contributing to sea-level rise.

- Thanks to Europe’s Copernicus environmental monitoring program, we have the Sentinel satellites to deliver essential information about what’s happening to our planet. This is especially important for monitoring remote inaccessible regions like the poles.

- ESA’s Mark Drinkwater said, “Having the Copernicus Sentinels in combination with research missions like CryoSat-2 is essential for monitoring ice volume changes in response to climate warming. In particular, the combination of year-round data from these microwave-based satellite tools provides critical information with which to understand ice-shelf fracture mechanics and changes in dynamic integrity of Antarctic ice shelves.”

• June 13, 2017: On 20 May, over a million tons of dirt and rock buried part of California’s Highway 1 along the Pacific coastline in the state’s Big Sur region. In addition to cutting off the route, the landslide added some 5 hectares of land to the shoreline. — Sentinel-1’s radar shows that the ground that slid down the mountain was moving in the two years before the landslide. ³⁴⁾

• May 12, 2017: Rapid acceleration of an Arctic glacier over the past year has been detected by the Copernicus Sentinel-1 satellites. Sitting on Norway’s Spitsbergen island in the Svalbard archipelago, the Negribreen glacier has recently seen a surge in ice surface speed, increasing from 1 m to 13 m a day over the winter. ³⁵⁾

- When a glacier ‘surges’ a large amount of ice flows to the end in an unusually short time. While the causes are not completely understood, they are believed to be linked to changes in the amount of heat or water in the lowest layers of the glaciers.

- The last time Negribreen experienced a surge like this was in the 1930s, as documented in aerial photographs. At that time, it advanced almost 12 km into the fjord in one year along a 15 km-wide section of the front. Since then the front of the glacier had been steadily retreating, with large icebergs breaking off.

- This latest jump in speed began in July 2016 and has been climbing ever since – even over the cold winter months. - Monitoring glaciers in areas prone to bad weather and long periods of darkness – like the Arctic – was difficult before the advent of satellites. Radar satellites can ‘see’ through clouds and in the dark, and Sentinel-1 offers frequent and systematic coverage of the Arctic.

- A team of scientists working under ESA’s Climate Change Initiative in the Glaciers_cci project are using satellite radar and optical coverage to map glaciers at different times and determine their changes in extent, elevation and speed.

- A team of scientists working under ESA’s Climate Change Initiative in the Glaciers_cci project are using satellite radar and optical coverage to map glaciers at different times and determine their changes in extent, elevation and speed.

- “Sentinel-1 provides us with a near-realtime overview of glacier flow across the Arctic, remarkably augmenting our capacity to capture the evolution of glacier surges,” said Tazio Strozzi from Swiss company Gamma Remote Sensing and scientist on Glaciers_cci.

- “This new information can be used to refine numerical models of glacier surging to help predict the temporal evolution of the contribution of Arctic glaciers to sea-level rise.”

• May 2, 2017: Over two decades of observations by five radar satellites show the acceleration of ice loss of 30 glaciers in Antarctica’s Western Palmer Land in the southwest Antarctic. ³⁶⁾

- Radar is particularly suited for monitoring polar regions that are prone to bad weather and long periods of darkness because it can collect information regardless of cloud cover, day or night. Mapping 30 glaciers in the region, the research team found that between 1992 and 2016, most of the glaciers sped up by 20 and 30 cm per day. This is equivalent to an average 13% increase in flow speed across the area as a whole (Figure 32).

- The study in Geophysical Research Letters combines over 24 years of radar data from satellites including ESA’s Envisat and ERS missions, as well as from the Copernicus Sentinel-1 mission. ³⁷⁾

- A decrease in the mass and volume of Western Palmer Land has raised the prospect that ice speed has increased in this marine-based sector of Antarctica. To assess this possibility, we measure ice velocity over 25 years using satellite imagery and an optimized modelling approach. More than 30 unnamed outlet glaciers drain the 800 km coastline of Western Palmer Land at speeds ranging from 0.5 to 2.5 m/day, interspersed with near-stagnant ice. Between 1992 and 2015, most of the outlet glaciers sped up by 0.2 to 0.3 m/day, leading to a 13 % increase in ice flow and a 15 km³/yr increase in ice discharge across the sector as a whole. Speedup is greatest where glaciers are grounded more than 300 m below sea level, consistent with a loss of buttressing caused by ice shelf thinning in a region of shoaling warm circumpolar water.

- The two-satellite Sentinel-1 mission for Europe’s Copernicus program routinely monitors polar areas at a high resolution, continuing the long-term data record from European satellites.

• April 20, 2017: Two Sentinel-1 radar images from 7 and 14 April 2017 were combined to create this interferogram showing the growing crack in Antarctica’s Larsen-C ice shelf (Figure 33). Polar scientist Anna Hogg said: “We can measure the iceberg crack propagation much more accurately when using the precise surface deformation information from an interferogram like this, rather than the amplitude – or black and white – image alone where the crack may not always be visible.” ³⁸⁾

- When the ice shelf calves this iceberg it will be one of the largest ever recorded – but exactly how long this will take is difficult to predict. The sensitivity of ice shelves to climate change has already been observed on the neighboring Larsen-A and Larsen-B ice shelves, both of which collapsed in 1995 and 2002, respectively.

- These ice shelves are important because they act as buttresses, holding back the ice that flows towards the sea.

• April 21, 2017: Earthquake Emergency Management Service in Italy. — A series of strong earthquakes struck Central Italy starting in August 2016, killing over 300 people, injuring some 360 and leaving over 2000 without homes. The Copernicus Emergency Management service was activated by the Italian Civil Protection authorities during this period and produced a total of 120 maps of the damaged areas, supporting their decision-making, rescue and aid delivery activities during these disastrous events. ³⁹⁾

- Susceptible tectonics: Italy’s tectonic and geological characteristics make it a country which is particularly susceptible to the risk of major earthquakes. It straddles the boundary between the Eurasian and African tectonic plates in the south, and a complex series of fault lines run down the entire length of the country along the Apennine mountain chain, collectively known as the Apennine fault. This geological “spine” is clearly visible in the map below, produced by the Italian National Institute for Environmental Protection and Research, ISPRA (Istituto Superiore per la Protezione e la Ricerca Ambientale).

- A series of major earthquakes: During the period between the end of August 2016 and January 2017, a series of significant earthquakes ravaged Central Italy:

1) 24 August 2016: A large earthquake measuring 6.2 Mw (Moment magnitude scale) struck Central Italy in the early hours of the morning.

2) 26 October 2016: Two months later, the Marche region was hit by two major earthquakes on the same day, measuring 5.4 and 5.9 Mw, respectively. Within a week, Umbria suffered a massive 6.5 Mw earthquake.

3) 18 January 2017: A set of large earthquakes struck Lazio and Abruzzo, of which the largest measured 5.7 Mw.

Large earthquakes are usually accompanied by large numbers of smaller shocks of varying intensity, some occurring prior to the main quake. These smaller events can amplify the destruction of the main tremor by further weakening already damaged buildings and infrastructure. The Italian Institute for Geophysics and Volcanology, INGV (Istituto Nazionale di Geofisica e Vulcanologia) maintains a network of sensors across Italy to measure earthquakes. The map (Figure 35) shows the earthquakes recorded by INGV in the regions of Central Italy between August 2016 and February 2017; the total number registered exceeds 45.000, and the sheer quantity and density of the events is overwhelmingly apparent.

• April 7, 2017: EMSA (European Maritime Safety Agency), based in Lisbon, Portugal, provides technical assistance and support to the European Commission and Member States, amongst others, in the development and implementation of EU maritime legislation. Its mission is to ensure a high, uniform and effective level of maritime safety, maritime security, prevention of and response to pollution from ships, as well as response to marine pollution caused by oil and gas installations. ⁴⁰⁾

- Satellites, with their sophisticated sensors, provide routine, cost-effective, wide-area surveillance over maritime zones. Furthermore, they can be pointed to a targeted location for monitoring specific operations and gather material in response to intelligence information. Earth observation contributes to maritime surveillance to help manage the actions and events that can have an impact on maritime safety and security, including marine pollution, accident and disaster response, search and rescue, as well as fisheries control.

- EMSA also operates CleanSeaNet, a satellite-based oil spill surveillance and vessel detection service. It offers assistance to participating States for the following activities:

1) identifying and tracing oil pollution on the sea surface

2) monitoring accidental pollution during emergencies

3) contributing to the identification of polluters.

- The CleanSeaNet service is based on radar satellite images, covering all European sea areas, which are analyzed in order to detect possible oil spills on the sea surface. When a possible oil spill is detected in national waters, an alert message is delivered to the relevant country. Analyzed images are available to national contact points within 30 minutes of the satellite passing overhead. Approximately 2,000 images are ordered and analyzed per year.

- The service, which is integrated into national and regional pollution response chains, aims to strengthen operational responses to accidental and deliberate discharges from ships, and assist participating States to locate and identify polluters in areas under their jurisdiction.

- Each coastal State has access to the CleanSeaNet service through a dedicated user interface, which enables them to view ordered images. Users can also access a wide range of supplementary information through the interface, such as oil drift modelling (forecasting and backtracking), optical images, and oceanographic and meteorological information.

- SAR satellite images cannot provide information on the nature of a spill (for instance whether it is mineral oil, fish or vegetable oil, or other), but spills from vessels often appear as long, linear dark lines (indicating a substance discharging as the vessel is moving), with a bright spot (the vessel) at the tip. Vessel detection is also available through the CleanSeaNet service. If a vessel is detected in a satellite image, its identity can often be determined by correlating the satellite data with vessel positioning reports from the European monitoring systems operated at EMSA, such as SafeSeaNet.

- The Sentinel-1 mission supports detection of illegal oil spills. ⁴¹⁾

Legend to Figure 37: In the false-color image, the temporal average, minimal and maximal backscattering values are represented for every pixel in the red, green and blue bands. Urban conglomerations, for example, reflect strongly and appear as prominent, bright areas. Water bodies deflect a large proportion of the oblique synthetic aperture radar beams from the satellite and are therefore dark. Vegetated regions are distinguished by comparatively high minimal backscatter, which causes forests and meadows to appear in green tones. Temporally dynamic land cover types, such as crop acreage, have changed considerably during the acquisition period and appear lilac in the data product.

Legend to Figure 38: This animation shows the TimeScan Landsat data derived for the Pearl River delta in China for 2002–03 and 2014–15. The illustrated TimeScan RGB images are composed of the temporal maximum built-up index in red, the maximum vegetation index in green and the temporal mean value of the water index in blue. A specific image analysis algorithm developed by DLR in ESA’s SAR4Urban project uses the TimeScan data to map the extent of the built-up area (highlighted in black in the animation) in order to finally pinpoint the urban growth that took place in the region over the last 10 years.

• March 31, 2017: This Sentinel-1 radar composite image (Figure 39) takes us to the northeastern tip of Ellesmere Island (lower-left), where the Nares Strait opens up into the Lincoln Sea in the Canadian Arctic. ⁴⁵⁾

- The image was created by combining three radar scans from Copernicus Sentinel-1 captured in December, January and February. Each image has been assigned a color – red, green and blue – and create this colorful composite when combined. Colors show changes between acquisitions, such as the movement of ice in the Lincoln Sea, while the static landmass is grey. - The obvious distinction between the red and yellow depicts how the ice cover has changed over the three months.

- The maximum extent of Arctic sea ice hit a record low this winter. Scientists attribute the reduced ice cover to a very warm autumn and winter, exacerbated by a number of extreme winter ‘heat waves’ over the Arctic Ocean.

- In the center-left on the land, we can see a straight, dark link with a circle at its left end. This is the runway for Alert – the northernmost known settlement in the world. Inhabited mainly by military and scientific personnel on rotation, Alert is about 800 km from the North Pole.

- A team of researchers on the CryoVex/Karen campaign was recently in Alert validating sea-ice thickness measurements from the CryoSat-2 satellite and testing future satellite mission concepts. ⁴⁶⁾

- Taking off from Alert, the team flew two aircraft equipped with instruments that measure sea-ice thickness at the same time the CryoSat-2 satellite flew some 700 km overhead. The measurements from the airborne campaign will be compared to the satellite measurements in order to confirm the satellite’s accuracy.

- A team will also make ground measurements of snow and ice along a CryoSat-2 ground track in April. Ground campaigns like this provide a wealth of data that help scientists better understand how the Arctic is changing and, ultimately, how climate is changing.

• March 5, 2017: Since the 1920s, excessive pumping of groundwater at thousands of wells has caused land to subside, or sink, by as much as 8.5 meters in sections of California’s San Joaquin Valley. This subsidence is exacerbated during droughts, when farmers rely heavily on groundwater to sustain one of the most productive agricultural regions in the United States. ⁴⁷⁾

- Subsidence is a serious and challenging concern for California’s water managers, putting state and federal aqueducts, levees, bridges and roads at risk of damage. Already, long-term land subsidence has damaged thousands of public and private groundwater wells throughout the San Joaquin Valley. Furthermore, the subsidence can permanently reduce the storage capacity of underground aquifers, threatening future water supplies. It’s also expensive. While there is no comprehensive estimate of damage costs associated with subsidence, state and federal water agencies have spent an estimated $100 million on related repairs since the 1960s.

- To determine the extent to which additional groundwater pumping associated with California’s recent historic drought has affected land subsidence in the Central Valley, California’s Department of Water Resources (DWR) commissioned NASA/JPL ( Jet Propulsion Laboratory) to use its expertise in collecting and analyzing airborne and satellite radar data. An initial report from JPL in August 2015 analyzed radar data from several different sensors collected between 2006 and early 2015. Due to the continuing drought, DWR subsequently commissioned JPL to collect and analyze new radar images from 2015 and 2016 to update DWR.

- Several trouble spots that were identified in 2015 have continued to subside at rates as high as 0.6 m per year. Significant subsidence was measured in subsidence bowls near the towns of Chowchilla, south of Merced; and Corcoran, north of Bakersfield. These bowls cover hundreds of square kilometers and continued to grow wider and deeper between May 2015 and September 2016. Subsidence also intensified near Tranquility in Fresno County, where the land surface has settled up to 51 cm in an area that extends 11 km.

- The map of Figure 40 shows the total subsidence in part of the San Joaquin Valley between May 2015 and September 2016 as observed by the ESA (European Space Agency) Sentinel-1A satellite and analyzed by scientists at JPL. The areas of most extensive subsidence appear in shades of yellow and bright green.

- JPL scientists plotted the history of subsidence of several sites in the mapped areas and found that for some areas in the San Joaquin Valley, subsidence slowed during the winter of 2015-16 when rainfall matched crop water needs. “While we can see the effect that rain has on subsidence, we know that we’ve run a groundwater deficit for some time, so it will take a long time to refill those reservoirs,” said JPL report co-author Tom Farr. ⁴⁸⁾

- Cathleen Jones, a co-author and scientist from JPL, said being able to pinpoint where subsidence is happening helps water resource managers determine why it is happening. “If you see a subsidence bowl, then something is going on at the center of the bowl that is causing the land to sink—for example, high levels of groundwater pumping,” she said. “We can locate problem spots so the state can focus on those areas, saving money and resources. We find the needle in the haystack, so to speak.”

- The researchers compared multiple satellite and airborne interferometric synthetic aperture radar (InSAR) images of Earth’s surface to show how subsidence varies over space and time. InSAR is routinely used to produce maps of surface deformation with approximately centimeter-level accuracy. The 2015 and 2017 reports included data from Sentinel-1A, NASA’s UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar), Japan’s PALSAR on ALOS-2, and Canada’s RADARSAT-2.

- “The rates of San Joaquin Valley subsidence documented since 2014 by NASA are troubling and unsustainable,” said DWR Director William Croyle. “Subsidence has long plagued certain regions of California. But the current rates jeopardize infrastructure serving millions of people. Groundwater pumping now puts at risk the very system that brings water to the San Joaquin Valley. The situation is untenable.”

• February 24, 2017: California has seen some heavy rains recently after years of drought, filling many of the state’s reservoirs. The rising waters are evident in this radar image from the Copernicus Sentinel-1 satellite mission over part of the San Joaquin Valley. ⁴⁹⁾

- The three water bodies pictured in Figure 41 are Lake Kawhea (in Tulare County) in the upper right, Bravo Lake to its left and Lake Success (near Porterville on the Tule River) in the lower right. This image was created by combining two scans from Sentinel-1’s radar on 15 December and 26 January, and assigning each scan a color. Combined, the colors reveal changes, such as the red coloring in the reservoirs showing the water level increase.

- Officials have begun to release water from Lake Success as heavy rains have nearly filled it to capacity, and the outflow is sometimes exceeding the inflow in these days.

- The problem of too much water is in stark contrast from the situation in previous years, when drought led to water shutoffs and cutoffs, severely hindering yields in the San Joaquin Valley – a major agricultural region. Major crops include grapes, cotton, nuts and fruits, with productivity relying on irrigation from surface water diversions and groundwater pumping from wells.

- Agricultural structures dominate this radar composite image. Like the reservoirs, colors reveal changes between December and January such as vegetation growth or harvests.

- Along the right side of the image, we can see the foothills of the Sierra Nevada mountains.

• February 16, 2017: Following the appearance of a large crack in the ice shelf close to the Halley VI research station of BAS (British Antarctic Survey) in Antarctica, information from the Copernicus Sentinel-1 and Sentinel-2 satellites helped to decide to close the base temporarily. ⁵⁰⁾

- Nourished by an inflow of ice from grounded glaciers and snow accumulating on its surface, Brunt Ice Shelf is a floating ice sheet in the Weddell Sea Sector of Antarctica. The floating ice moves steadily towards the ocean, where it occasionally calves off as icebergs. Cracks often appear on shelves as the ice deforms. However, rapidly expanding cracks indicate impending calving.

- Since the Halley VI base of BAS was only 17 km from the crack that appeared last October, ENVEO – a company that uses satellite data for cryosphere studies – and the Survey used radar images from Sentinel-1 and optical images from Sentinel-2 to monitor the situation.

- Dubbed Halloween Crack, it was lengthening inland as fast as 600 m a day in November and December 2016. Halley was designed to be relocated if the ice becomes dangerous. In fact, it had already been moved 23 km inland during last Antarctica’s summer months because another ice chasm had begun to show signs of growth. ⁵¹⁾

- The station sits on Antarctica’s 150 m thick Brunt Ice Shelf. This floating ice shelf flows at a rate of 0.4 km per year west towards the sea where, at irregular intervals, it calves off as icebergs. Halley is crucial to studies into globally important issues such as the impact of an extreme space weather event, climate change, and atmospheric phenomena. It was scientific investigations from this location that led to the discovery of the Antarctic Ozone Hole in 1985.

- Normally, around 70 people live and work at the base during the summer and fewer than 20 during the winter. However, this is the first winter that the base has been completely closed.

- Thomas Nagler, ENVEO CEO, said, “We get Sentinel-1 and Sentinel-2 data shortly after acquisition so we are able extract information on the crack’s progression and deliver this information to our Survey colleagues very quickly.” Hilmar Gudmundsson, Survey lead scientist, added, “The frequency of Sentinel-2 images and Sentinel-1 radar products allows us to follow in detail and almost in real time the development of the crack as it grows week by week. This also provides us with essential information for ice-deformation models, leading to a deeper understanding of such events.”

- Mark Drinkwater, head of ESA’s Earth observation mission, added “Routine Antarctic summer observations by the combination of Copernicus Sentinel-2A and Sentinel-1A and -1B are now demonstrating their value for monitoring rapid environmental change and providing information crucial to informed decisions on matters of safety and security in Antarctica.

• February 3, 2017: Climate change-driven glacial melt is causing landslides in alpine regions. Data from the Sentinel-1 satellite mission are being inserted into a new cloud computing system to monitor such hazards globally. ⁵²⁾

- The Aletsch Glacier, the largest in the Alps, is experiencing an average retreat of about 50 m a year. The adjacent rocks that were previously constrained by the ice mass are progressively being released, generating slope instabilities. For this reason, the Aletsch region is a unique place where scientists can investigate how changes in glaciers affect the long- and short-term evolution of rock slope stability.

- To monitor the progressive changes occurring throughout a 2 km² area southeast of the glacier – called the Moosfluh slope – the Chair of Engineering Geology at the Swiss Federal Institute of Technology in Zurich (ETHZ) installed ground-based instruments in 2013.

- Between September and October 2016, Moosfluh experienced an abnormal acceleration. The deformation generated several deep cracks and rock failures, hindering access to hiking paths visited by tourists, and affecting a cable car station located near the crest of the slope.

Legend to Figure 43: Land deformation speed of the Moosfluh area observed by the Sentinel-1 satellite from August to November 2016. The monitoring system installed by the Chair of Engineering Geology at ETHZ includes two Robotized Total Stations (RTS1 and RTS2), which monitor the evolution of surface displacements at point targets located on the unstable area (white and red dots). The results obtained from satellite data helped scientists to define the extension of the most active area and identify locations to place additional monitoring targets (red dots),

• January 30, 2017: A crack in the Larsen-C ice shelf in on the Antarctic Peninsula first appeared several years ago, but recently it has been lengthening faster than before. Carrying radar that can ‘see’ through the dark, the Copernicus Sentinel-1 satellites are monitoring the situation. The animation shows that the fissure has opened around 60 km since January last year. And, since the beginning of this January it has split a further 20 km so that the 350 m-thick shelf is held only by a thread. The crack now extends around 175 km. ⁵³⁾

- When the ice shelf calves this iceberg it will be one of the largest ever recorded – but exactly how long this will take is difficult to predict. The neighboring Larsen-A and Larsen-B ice shelves suffered a similar fate with dramatic calving events in 1995 and 2002, respectively. —These ice shelves are important because they act as buttresses, holding back the ice that flows towards the sea.

• November 25, 2016: The Sentinel-1 satellites have shown that the Millennium Tower skyscraper in the center of San Francisco is sinking by a few centimeters a year. Studying the city is helping scientists to improve the monitoring of urban ground movements, particularly for subsidence hotspots in Europe. ⁵⁴⁾

- Completed in 2009, the 58-storey Millennium Tower has recently been showing signs of sinking and tilting. Although the cause has not been pinpointed, it is believed that the movements are connected to the supporting piles not firmly resting on bedrock. - To probe these subtle shifts, scientists combined multiple radar scans from the Copernicus Sentinel-1 twin satellites of the same area to detect subtle surface changes – down to millimeters. The technique works well with buildings because they better reflect the radar beam.

- It is also useful for pinpointing displacement hotspots over large areas, thanks to Sentinel-1’s broad coverage and frequent visits. Working with ESA, the team from Norut, PPO.labs and Geological Survey of Norway have also mapped other areas in the wider San Francisco Bay Area that are moving. These include buildings along the earthquake-prone Hayward Fault, as well as subsidence of the newly reclaimed land in the San Rafael Bay.

- An uplift of the land was detected around the city of Pleasanton, possibly from the replenishment of groundwater following a four-year drought that ended in 2015.

- European cities experience similar subsidence, and the San Francisco study is helping because it contains a multitude of features (Ref. 54).

- For example, the area around Oslo’s train station in Norway is reclaimed land. Newer buildings, such as the nearby opera house, have proper foundation into bedrock, but the older parts of the station experience severe subsidence.

- “Experience and knowledge gained within the ESA’s Scientific Exploitation of Operational Missions program give us strong confidence that Sentinel-1 will be a highly versatile and reliable platform for operational deformation monitoring in Norway, and worldwide,” noted John Dehls from the Geological Survey of Norway.

- The studies of San Francisco and Oslo are paving the way for moving from targeted case studies to a nationwide or even continental-scale land deformation service.

- “The Copernicus Sentinel-1 mission is, for the first time, making it possible to launch operational national deformation mapping services,” said Dag Anders Moldestad from the Norwegian Space Center. The open data policy and regular coverage plan of Copernicus promise cost-efficient and reliable services. “In Norway, we have already initiated a framework project to provide nationwide basic deformation products to the public, with a free and open data policy. Many other countries in Europe are also working towards setting up similar services,” noted Dr. Moldestad.

- The Sentinel-1 twins provide ‘radar vision’ for Europe’s Copernicus environment monitoring program. In addition to watching land movements, they feed numerous other services for monitoring Arctic sea ice, routine sea-ice mapping, surveillance of the marine environment, mapping for forest, water and soil management, and mapping to support humanitarian aid and crisis situations.

• November 11, 2016. The Sentinel-1 image of Figure 49 shows the Virunga Mountains in East Africa and their volcanoes. While most are dormant, two of the eight volcanoes are active, with the most recent eruptions in 2006 and 2010. ⁵⁹⁾

- The mountains are on the Albertine Rift, where the Somali Plate is splitting away from the rest of the African continent. The area is one of Africa’s most biologically diverse regions, but high human population density, poverty and conflict pose a challenge to conservation. Across the mountain range, however, a series of national parks has been established to protect the fauna and flora.

- In this image, we can easily identify the delineation between the protected and non-protected lands – the green, orange and yellow dots indicate changes in the surface of non-protected lands between the radar scans that make up this composite image. These changes are primarily in vegetation as the land surrounding the mountains is blanketed with agricultural plots. In particular, we can see the grid-like pattern of agriculture is visible in the green and yellow square at the center of the image.

• November 3, 2016: In the early hours of 30 October 2016, a 6.5 magnitude earthquake struck central Italy. The team od scientists combined several pairs of Sentinel-1 radar images acquired between 25 October and 1 November 2016 to analyze the ground displacements caused by the quake. ⁶⁰⁾

- New information on the effects of the 30 October earthquake that struck central Italy continues to emerge as scientists analyze radar scans from satellites. Using radar imagery from the Copernicus Sentinel-1 satellites, Italian experts have identified significant east–west displacements of the ground in the area struck by the earthquake. An eastwards shift of about 40 cm was mapped in the vicinity of Montegallo, while a westwards shift of about 30 cm is centered in the area of Norcia (Figure 50).

- The team of scientists from the Institute for Electromagnetic Sensing of the Environment of the National Research Council and the National Institute of Geophysics and Volcanology combined radar scans taken before and after the event to map centimeter-scale changes. Vertical displacement is also evident, with the ground sinking 60 cm around Castelluccio but rising by about 12 cm around Norcia (Figure 51).

• October 28, 2016: The Geohazards Exploitation Platform gives users direct access to large Earth-observation datasets for areas at risk of geohazards such as earthquakes and volcanic activity. Radar ‘interferometry’ involves taking successive radar images of the same location and combining them to produce rainbow-hued ‘interferograms’. Like playing spot the difference, the slightest shift between images gives rise to distinct interference fringes, resembling contour lines on a map. ⁶¹⁾

- Pairs of Sentinel-1A radar images from consecutive passes over the same spot on Earth’s service are processed continuously and automatically to provide medium-resolution (200 m) images. This, and related interferograms, allows users to identify ground movement and other changes that may have occurred between satellite acquisitions. The service currently covers tectonic areas in Europe. Covering three million km², this represents 360 interferometric pairs every 12 days.

- The image of Figure 53 was generated automatically on the Geohazards Exploitation Platform and combines images captured by Sentinel-1A before and after the quakes. The Geohazards Exploitation Platform gives users direct access to large Earth-observation datasets for areas at risk of earthquakes or volcanic activity, for example. ⁶²⁾

Pairs of Sentinel-1A radar images from consecutive passes over the same spot on Earth’s service are processed continuously and automatically to provide medium-resolution (200 m) images. These interferograms allow users to identify ground movement and other changes that may have occurred between satellite acquisitions. Although the service only covers Europe, this illustrates how information on major events can be made available to users. Over the next months, the browse service will be ramped up gradually to cover the global tectonic ‘mask’. This mask corresponds to regions where the shape of the ground is deforming because of tectonic activity and prioritised by the geohazards user community.

“The quick-browse service has been under way across European tectonic regions since January, harnessing automated processing developed by the DLR German Aerospace Center,” explains Fabrizio Pacini of Terradue, overseeing the Platform. “Our plan next year is to gradually scale up to cover the entire world’s tectonic regions, which adds up to a quarter of Earth’s land surface. Such wide-area coverage is really unprecedented. It is a crucial step towards empowering society at large to reduce the risk from earthquakes and volcanoes.”

- Today, it is a well-established technique used to give authoritative snapshots of ground movements following events such as the recent earthquakes in central Italy. — Earth scientists were surprised in the 1980s when centimeter-accuracy GPS networks revealed previously unsuspected motion along tectonic plates, occurring between larger-scale seismic events. ⁶³⁾

Combined radar scans are sensitive down to a level of millimeters and over wide areas, compared to point-by-point GPS measurements, but the process demands heavy computing power. “The real step change here is that they are being produced across extended areas on an entirely automated basis,” adds Fabrizio.

- The service is processing an average 50 image pairs per day across Europe from the Sentinel-1A and Sentinel-1B satellites, with six days between coverage.

- Next year, this will increase to 130 pairs per day, with a maximum of 24 days and potentially 12 days between acquisitions outside Europe, involving the daily processing of 1 terabyte of data, with additional higher resolution produced on request.

Processing on such a grand scale is enabled by the online, cloud-based Geohazards Exploitation Platform, specifically tailored for working with vast amounts of satellite data.

• Sept. 16, 2016: Southern China’s Poyang Lake is the largest freshwater lake in the country. Located in Jiangxi province, this lake is an important habitat for migrating Siberian cranes, many of which spend the winter there. The lake is also home to the endangered finless porpoise, a freshwater mammal known for its high level of intelligence. Amid fears that it would soon become extinct, the porpoise made headlines last year when the Chinese government moved eight of them from Poyang Lake to two secure habitats in an effort to increase the population over the coming years. ⁶⁵⁾

- One study found that, without action, the current rate of population decrease would likely mean extinction by 2025.

- For the human population, Poyang is one of China’s most important rice-producing regions, although local inhabitants must contend with massive seasonal changes in water level.

- Local scientists collaborating with ESA through the Dragon program have identified an overall drop in water level in the lake over the last decade, but the El Niño weather phenomenon earlier this year caused precipitation levels to increase and water levels of the lake to rise.

• June 22, 2016: The twin Sentinel-1 satellites have – for the first time – combined to show their capability for revealing even small deformations in Earth’s surface. Following its orbital maneuvers, the recently launched Sentinel-1B satellite reached its designated orbit position on 15 June. The satellite is now orbiting Earth 180° apart from its twin, Sentinel-1A, at an altitude of almost 700 km. With both satellites finally in the same orbit, together they can cover the whole globe every six days. — It has now been demonstrated that future images acquired by the pair can be merged to detect slight changes occurring between scans. ⁶⁷⁾

- The rainbow-colored patterns (Figure 57) are related to topography, and they demonstrate that the two satellites’ identical radars are accurately synchronized, pointing in the same direction and that the satellites are in their correct orbits.

- Once commissioning is completed in mid-September, the pair will be ready to deliver data for the systematic and routine monitoring of Earth surface deformation and ice dynamics.