The Sentinel-1 mission facilitates services that include monitoring of Arctic sea-ice extent, routine sea-ice mapping, surveillance of the marine environment (including oil-spill monitoring and ship detection for maritime security), monitoring land-surface for motion risks, mapping for forest, water and soil management, and mapping to support humanitarian aid and crisis situations. While the mission offers timely information for a multitude of operational applications, it continues more than 20 years of radar imagery. This archive is not only essential for practical applications that need long time series of data, but also for understanding the long-term impacts of climate change and planning for a sustainable future.
Oceans and Ice
Sentinel-1 provides synthetic aperture radar (SAR) images to generate timely maps of sea-ice conditions for safe passage in increasingly busy Arctic waters. The radar can 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.
Oil spill monitoring
Sentinel-1 provides continuous sampling of the open ocean, offering information on wind and waves. These data are useful for understanding interactions between waves and currents and to improve efficiency for shipping and wave-energy applications, potentially producing economic benefits. In addition, these observations can be used to track the paths of oil slicks and other pollution.
The mission opens up new possibilities for many land applications. Frequent satellite revisits over the same area allow close monitoring of changes in land cover, particularly useful for keeping an eye on tropical forests that are typically shrouded by cloud cover, and for detecting illegal timber harvesting worldwide.
Land-cover information is also important for agricultural practices, to estimate crop acreage, to provide soil moisture information, and to forecast yields. Moreover, this new mission is the only European satellite specifically designed for fast response to emergencies and disasters such as flooding and earthquakes.
Radar images — such as those provided by Sentinel-1’s C-band SAR — are the best way of tracking land subsidence and structural damage through interferometric SAR (InSAR). InSAR combines two or more radar images over the same area to detect changes occurring between acquisitions, facilitating monitoring of even slight ground movement — down to a few millimeters — across wide areas. As well as being a valuable resource for urban planners, this kind of information is essential for monitoring shifts from earthquakes, landslides, and volcanic uplift.
The C-band SAR on Sentinel-1 can provide images with a resolution of 10 m and within hours of acquisition to aid emergency response. This imagery can be used for precise terrain deformation monitoring over landslide, seismic, or subsidence areas by providing regular and frequent interferometric observations. It can also support impact assessment for many types of hazard including hydrometeorological and geological events.
Sentinel-1’s radar ability to see through clouds, rain, and dark makes it particularly useful for monitoring floods. Images acquired before and after a flood offer immediate information on the extent of inundation and support assessments of property and environmental damage. The mission also provides information on wind and waves, which can be used to track the paths of oil slicks and other pollutants.
Earthquake Monitoring of California’s Napa Valley. © ESA/DLR
Tokyo, image of a megacity, © ESA
High desert, U.S. Northwest, © ESA