ISRO explains how it used the SCATSAT-1 to monitor floods across the country this monsoon

ISRO used the SCATSAT-1 to track flooding across the nation during the monsoon, with a special focus on Gujarat and Rajasthan. Monsoon activity in West Bengal, Uttar Pradesh, Assam and Bihar were also tracked. The satellite used data based on backscattering and brightness temperatures of the earth to monitor the flood situations. ISRO was able to capture a high resolution dataset by scanning overlapping areas with the satellite.

Flooding in Gujarat. Image: ISRO.

The backscattering and brightness data were combined to figure out which regions were inundated and which regions were only partially submerged. The satellite was also used to figure out the wetness of the soil in the affected areas, on how saturated or dry the regions were. Floods along the Brahmaputra and the Ganga were tracked using this method. In Gujarat, extreme floods were observed in the districts of Ahmedabad, Mehsana, Kheda, Banskantha, Bhavnagar but Bharuch was relatively dry.

The INSAT-3D/3DR provides observations of cloud cover and rainfall, but is unable to image the inundation on the ground through the thick clouds during monsoons. The instruments on the SCATSAT-1 were able to penetrate the cloud cover to make the necessary observations. The data from the SCAT-SAT-1 was correlated with observations from the Sentinel-1A, which is an earth observation satellite equipped with a Synthetic-aperture radar. ISRO has provided an animation of the floods during June 2017.

The SCATSAT-1 is an earth observation satellite that was launched on the PSLV-C35 mission in September 2016. The satellite gets its name from its primary payload, a Ku-band pencil-beam scatterometer. The SCATSAT-1 orbits the earth at an altitude of 720 km and provides data for detection of cyclones and weather forecasting. The SCATSAT-1 is a continuity mission to the OceanSat-2 and has a planned mission duration of five years.