The Copernicus Sentinel-1 mission provides all-weather, day-and-night radar imagery for the global monitoring of Earth’s land and oceans. The mission and data support critical areas such as environmental management, disaster response and climate change research.

Sentinel-1 data contributes to numerous Copernicus services and applications, including Arctic sea-ice monitoring, iceberg tracking, routine sea-ice mapping and glacier-velocity measurements. It also plays a vital role in marine surveillance, such as oil-spill detection, ship tracking for maritime security and monitoring illegal fishing activities.

Additionally, it is widely used for observing ground deformation caused by subsidence, earthquakes and volcanic activity, as well as for mapping forests, water and soil resources. The mission is crucial in supporting humanitarian aid and responding to crises worldwide.

The Sentinel-1 series began with Sentinel-1A, launched in April 2014, followed by Sentinel-1Bin 2016. Each satellite is equipped with a C-band synthetic-aperture radar (SAR) instrument which operates in four modes and provides a spatial resolution down to 5 m and a swath of up to 410 km.

Although Sentinel-1B was retired in 2022 due to an electrical failure, Sentinel-1A remains fully operational, and has far exceeded its life expectancy of seven years.

The upcoming launch of Sentinel-1C will restore the mission to its full strength as a two-satellite constellation.

Once in orbit, Sentinel-1C will continue the mission’s legacy, providing high-quality radar imagery to support scientific research and a wide range of applications. Notably, it introduces enhanced capabilities for monitoring maritime traffic, further expanding the mission’s utility.

In today's article, we explore the diverse range of applications for Copernicus Sentinel-1 data.

Interferometry for earthquake studies – Türkiye–Syria

On 6 February 2023, a series of earthquakes killed over 55,000 people in Türkiye and Syria, in the worst earthquakes the region has seen in 20 years.

This interferogram shows the coseismic surface displacement in the area near Gaziantep, generated from multiple Sentinel-1 scans – before and after the earthquakes.

By combining data from the Copernicus Sentinel-1 mission, acquired before and after the earthquake, changes on the ground that occurred between the two acquisition dates lead to the colourful interference patterns in the images, known as an ‘interferogram’, enabling scientists to quantify the ground movement.

These interferograms allows scientists to understand more about the nature of the earthquakes and the risk of further hazards in the future.

Sea ice monitoring – Bering Strait

Sea ice is one of the most important physical elements of the Bering Sea continental shelf. Unprecedentedly low sea ice cover in the northern Bering seas during winter in 2019 caused a cascade of impacts that abruptly transformed the regional marine ecosystem, compounding challenges faced by the communities that rely on it. This Sentinel-1 image shows the Bering Strait in March 2019, virtually ice-free. Few patches of sea ice are shown in light-blue colours.

Sentinel-1 data is essential for the Copernicus Marine Service (CMEMS), enabling safe navigation in icy waters, enhancing climate modelling and supporting the assessment of environmental changes in polar regions.

By providing timely and accurate sea ice information, Sentinel-1 helps CMEMS ensure the safety and sustainability of marine operations. Its radar imagery is particularly effective for producing high-resolution ice charts, distinguishing between thinner, navigable first-year ice and thicker, more hazardous multiyear ice, as well as monitoring icebergs and forecasting ice conditions in the increasingly busy Arctic waters.

Oil spills – Trinidad and Tobago

Before-and-after satellite images from Sentinel-1 show the extent of the oil spill off the coast of Trinidad and Tobago in February 2024. The incident occurred when the vessel The Gulfstreamran aground and capsized off the southern shores of Tobago Island, releasing oil into the surrounding waters.

Sentinel-1's radar is highly effective for monitoring oil spills, as it can detect subtle changes in the ocean surface caused by oil slicks. These slicks dampen wave motion, leaving distinct radar signatures that appear as dark smears on a lighter background. Since radar technology measures surface texture, oil spills are easily identifiable in the images.

Sentinel-1 is a cornerstone for maritime surveillance, providing high-resolution radar imagery to not only monitor oil spills, but also ship traffic and track illegal fishing activities. Sentinel-1 is particularly vital to the European Maritime Safety Agency’s (EMSA) CleanSeaNet, supplying 80% of the data used to detect and assess oil spills – supporting rapid response and maritime security across European waters.

Flood monitoring – Valencia, Spain

In October 2024, Spain suffered one of the worst floods in decades after torrential rains struck the eastern province of Valencia. The storms concentrated over the Magro, Turia and the Poyo river basins, releasing torrents of muddy water that turned village streets into rivers, destroyed homes and swept away bridges and vehicles.

The radar image above uses data from two image acquisitions (from 19 and 31 October 2024) to illustrate the severe flooding (in blue) of the Albufera National Park.

Sentinel-1 is ideal for flood monitoring because its Synthetic Aperture Radar (SAR) technology can penetrate clouds and operate in darkness, providing reliable imaging during extreme weather conditions when optical sensors might fail.

Data from Sentinel-1 is used extensively by the Copernicus Emergency Management Service (CEMS), providing critical data to support disaster response and recovery efforts.

Hurricane monitoring – Hurricane Helene

Hurricane Helene was a devastating tropical cyclone that produced a wide swath of damage and loss of life that extended from northwest Florida, US, where the storm made landfall on 26 September 2024, to Tennessee, Georgia and North Carolina.

Hurricane Helene was closely monitored using Sentinel-1 radar data to assess its wind field over the ocean surface. This technology plays a crucial role in understanding storm dynamics and predicting their impacts.

Satellite-based sensors, particularly those operating in microwave frequencies, can capture data on ocean surface wind speed and direction under various weather conditions. The Ocean Wind Field (OWI), derived from Sentinel-1, provided detailed estimates of wind vectors at 10 m above the ocean surface. This information is essential for meteorologists to analyse the storm's intensity and trajectory.

Iceberg monitoring – Antarctica

In 2021, Sentinel-1 witnessed Iceberg A-74, calve from Antarctica’s Brunt Ice Shelf. Radar images then showed the iceberg months later travelling spinning around the western tip of Brunt, brushing slightly against the ice shelf before continuing southwards.

Sentinel-1 is perfect for monitoring regions like Antarctica because its Synthetic Aperture Radar (SAR) technology can see through clouds, rain and darkness, ensuring continuous data collection in the continent's extreme conditions.

This capability allows Sentinel-1 to track glacial movement, measure ice loss and monitor changes in the ice sheet with remarkable precision, regardless of the persistent cloud cover or darkness in the polar night.

Deforestation - Mato Grosso, Brazil

This image of the Brazilian state of Mato Grosso has been created by combining three separate radar acquisitions from Sentinel-1 taken years apart to show change in crops and land cover over time.

Unlike images from satellites carrying optical or ‘camera-like’ instruments, images acquired with radar are interpreted by studying the intensity of the backscatter radar signal, which is related to the properties of the ground, such as its roughness.

While colours in grey here depict no changes between acquisitions, patches of blue, green and red indicate significant changes over time (from 2015-2019). As these coloured rectangular shapes portray, much of the tropical forest has been cut down and given over to farming.

Sentinel-1 is an invaluable tool for monitoring deforestation, thanks to its Synthetic Aperture Radar (SAR) technology, as it allows for the detection of changes in forest cover, even in areas with dense cloud cover or during nighttime. By analysing radar data over time, Sentinel-1 can track forest loss and land-use changes, offering crucial information for environmental monitoring.

Agriculture monitoring – Rice fields, Vietnam

This Sentinel-1 image shows part of the Mekong Delta – a major rice-producing region in southwest Vietnam. This image combines three radar acquisitions from Sentinel-1 taken around one month apart to show changes in crop and land conditions over time. The bright colours in the image come from changes on the ground that have occurred between acquisitions.

The combination of radar images from the Copernicus Sentinel-1 mission can help monitor and map the evolution of rice cultivation. Radar sensors are particularly useful owing to their ability to detect waterlogged ground and penetrate the humid cloud coverage typical of Asian rice-cultivating regions.

Bodies of water reflect the radar signal away from the satellite, making water appear dark. Ships in the river can be seen as bright, multi-coloured dots.

Sentinel-1 is highly effective for agricultural monitoring as it provides detailed information on soil moisture, crop structure and growth patterns, which are essential for assessing agricultural health and productivity.

Displacement monitoring – Jakarta, Indonesia

The Indonesian capital of Jakarta is home to 10 million people and is also one of the fastest-sinking cities in the world. Researchers suggest that parts of the megacity could be entirely submerged by 2050.

By using a large number of radar satellite images over a two-year period, it is possible to accurately calculate ground subsidence. This image shows the mean ground displacement rates based on Sentinel-1 radar data from 2017-2018. Areas in red show major displacement over time with some areas showing local sinking patterns reach around 12 cm per year.

By comparing radar images over time, data from Sentinel-1 can be used to generate detailed displacement maps, essential for tracking subsidence, landslides, volcanic activity and infrastructure stability.

Maritime traffic jam – Suez Canal, Egypt

 

In March 2021, a traffic jam in the Suez Canal captured global attention when the Ever Given, one of the world’s largest container ships, became lodged sideways across the waterway. The vessel blocked all traffic in both directions for six days, causing a significant disruption to global trade.

The Sentinel-1 images here highlight the impact of the blockage, showing routine maritime traffic in the left image before the jam, and the massive 400-meter vessel obstructing the canal in the image on the right.

Sentinel-1 is a valuable tool for monitoring ship traffic; its radar detects the sea surface, which reflects the signal away from the satellite, making the water appear dark. In contrast, metal objects like ships appear as bright dots against the dark ocean, allowing for easy identification and tracking.

Quelle: ESA