Above: Sentinel-3B MWR
Copyright  Airbus

It is one of the essential instruments of the Sentinel-3 spacecraft, measuring atmospheric humidity as supplementary information for tropospheric path correction of the altimeter signal. In addition, MWR data is useful to measure surface emissivity and soil moisture over land, surface energy budget investigations which support atmospheric studies and for ice characterisation.

 
These corrected measurements along with a digital elevation mode help the radar altimeter to work in SAR (Synthetic Aperture Radar) mode, which is much more precise and provides much better spatial resolution along the track.
 
The data produced will allow scientists to monitor sea-level changes, sea-surface temperature, manage water quality, and track marine pollution and biological productivity. It will also provide a land-monitoring service with wildfire detection, land-cover mapping and vegetation health monitoring. This will provide complementary data to the Sentinel-2 multispectral optical mission.
 
Airbus is also responsible for the Sentinel-3 spacecraft’s thermal architecture, which will ensure the correct performance during the extreme temperature variations the satellite will be subjected to in orbit and for the cryo-cooler system of the Sea and Land Surface Temperature Radiometer (SLSTR) instrument.

Above: Sentinel-3B tested.
Copyright  ESA / S. Corvaja
 
Sentinel-3 is the Copernicus operational wide-swath medium resolution ocean and land mission. It is designed to providing continuity to optical and altimetry data of the Airbus built Envisat mission, as well as the vegetation data of ERS and SPOT missions. This will ensure the long-term collection and operational delivery of high-quality measurements for ocean, land and atmospheric services.
 
Sentinel-3B, about the size and weight of a small car, is designed for an operating life of seven years, like its twin satellite Sentinel-3A launched two years ago. Its MWR is currently working in nominal and stable conditions after a successful in orbit verification phase.