Assessing early season drought condition using AMSR-E soil moisture product

Abstract

Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) soil moisture product was used to assess early season drought condition over Maharashtra State of India in summer monsoon (kharif). AMSR-E Soil Moisture Index (AMSR-E SMI) was calculated using AMSR-E soil moisture and soil textural information. The index had normalization to soil matrix and could be composited over a time scale. The index had statistically significant correlation (R 2 value 0.6 to 0.7) with rainfall during early kharif season (June to August). Spatio-temporal dynamics of AMSR-E SMI and its inter annual variability (2007 to 2010) were analysed at meteorological subdivision level. Persistent dryness was found in 2008 (drought year) and soil wetness was near normal in other years. Intermittent short dry spells were also monitored and quantified. Spatio-temporal variation of intensity and persistence of soil wetness as depicted by AMSR-E SMI had good correspondence with progression of sown area over Maharashtra. Geospatial information of sowing period soil wetness condition derived from AMSR-E SMI could be vital supplementary information in assessment of early season drought.