Sentinel-1 carries a C-band synthetic aperture radar. Unlike an optical sensor, it transmits and receives microwaves: acquisition does not depend on sunlight and can continue through clouds. That continuity helps monitor an area during cloudy periods and compare images from different dates.
Backscatter intensity depends on surface roughness, moisture, orientation and vegetation. After flooding, a pair of images can help identify surface change; in vegetated or mountainous terrain, the response is more complex and needs careful interpretation.
Radar is not a photograph and does not directly measure water depth, water quality or rock type. Terrain, viewing angle and processing all affect the result. A reliable map combines radar time series with other data, terrain analysis and, where needed, local observations.
