Scatterometry for land hydrology science and its applications

This study reports the potential of SCATSAT-1 scatterometer data for catchment-scale hydrological applications related with river water level estimation and flood detection. New approaches have been developed for estimation of river water levels and detection of surface flooding using Oceansat-II scatterometer (OSCAT) and SCATSAT-1 scatterometer-based high-resolution backscatter and brightness temperature (BT) datasets respectively. Ku-band sigma-0 and BT data, Shuttle Radar Topography Mission Digital Elevation Model and observed hydrometric data have been used in this study. Catchments of gauging sites and their influencing areas were delineated using the topography, wetness conditions and land-cover variations. OSCAT time series of scatterometer image reconstruction data were used to develop model function between basin water index and ground-observed river-stage datasets. Subsequently, inverting these functions on SCATSAT-1 observations, river water levels for 2017 were estimated at different gauging sites. A study on the magnitude of each flooding event in terms of intensity, duration and extent of area affected was also carried out using the scatterometer-based BT data analysis. The study demonstrated that high temporal resolution scatterometer data has the potential to fill the gap of coarser temporal resolution altimeters (10-35 days) for river heights and Synthetic Aperture Radar Data (7-25 days) for surface flooding with the advantage of capturing extreme events.