Synthetic Aperture Radar (SAR) imagery maps the surface microwave radar reflectivity at resolutions from a sub-meter to 100 m depending on the particular SAR satellite and mode. Since radar is an active sensor, sending a pulse with a return signal that is measured, the imagery is independent of the time of day. At typical radar frequencies, radar imagery can see through clouds and are considered “all-weather” instruments. Several geophysical parameters can be derived from SAR including sea surface wind speed, sea and lake ice types, surface algae scum features, and as an important resource for rapid response to oil spill detection.
The Sentinel-1 mission comprises a constellation of two polar-orbiting satellites, operating day and night performing C-band synthetic aperture radar (SAR) imaging, enabling them to acquire imagery regardless of the weather. Sentinel-1A and Sentinel-1B share the same orbit plane with a 180° orbital phasing difference. With both satellites operating, the repeat cycle is six days for the Great Lakes.
SAR Normalized Radar Cross Section (NRCS) imagery is will be updated during the winter season.