RISAT’s Silent Promise: Decoding Disasters with Synthetic Aperture Radar

Synthetic Aperture Radar (SAR) from satellites like India's RISAT program provides a reliable method for real-time flood intelligence, overcoming the limitations of optical imagery. The technique works by sending microwave beams and measuring the reflected energy, or backscatter, which causes smooth water surfaces to appear dark in contrast to rougher land. A multi-step data science pipeline is used to process this data, involving preparation, noise reduction, and change detection between pre- and post-flood images to map inundated areas. This process is refined using additional geographic data to remove false positives like permanent water bodies or steep slopes. While AI is an emerging tool, current operational flood mapping relies more on these physics-based methods and expert human judgment for greater reliability and consistency across different environments.