Microwave remote sensing application for monitoring of floods

Abstract

Many times heavy and continuous rains give rise to flooding in the rivers. Devastating floods occurred in rivers Ganga and Kosi in Bihar (India) and in Damodar and Hooghly rivers in West Bengal (India) during 2011. In the present paper, passive microwave remote sensing data is utilized for detection and monitoring of floods that occurred in Darbhanga (Bihar) and Midnapore (West Bengal) India, in the year 2011during monsoon season. Special Sensor Microwave Imager Sounder (SSMIS) brightness temperature (Tb) data at 19 GHz & 91 GHz in both vertical and horizontal polarisations and Soil Moisture and Ocean Salinity (SMOS) Tb data at 1.4 GHz are used to detect and monitor the flood occurrences. An attempt has been made to detect and monitor the flood events using 19 GHz Tb, difference of 19 and 91 GHz Tbs, and 1.4 GHz Tb, with both horizontal and vertical polarizations. Highest sensitivity to flood occurrence is observed for (19 GHz - 91 GHz) Tbs in horizontal polarization. Flood affected areas are mapped using (19 GHz - 91 GHz) Tbhs (Brightness temperatures with horizontal polarisation) values and compared with the Radarsat-1 images to show a general agreement between passive and active microwave remote sensing data. The comparison also shows an over-estimation of flooded area from passive microwave data.