Rainfall and soil wetness response to ENSO and soil wetness estimation from remote sensing data

Studies on water budget elements are of great importance in the context of geo-hydrological scenario. The estimation and analysis of soil wetness for a particular region is helpful in understanding the various mechanisms involved in the land surface hydrology. The present study attempts to understand the daily rainfall and soil wetness variations with respect to the geophysical indices of ENSO phases such as NINO 3 sea surface temperature and Southern Oscillation Index. The parameter soil wetness is derived from the water balance model on a daily basis. The study has been performed for the monsoon seasons of 1999 to 2002 over selected stations of Andhra Pradesh (12 degrees-20 degrees N; 76 degrees-86 degrees E). The study then proceeds in estimating the soil wetness using the brightness temperature data of Multichannel Scanning Microwave Radiometer of IRS-P4. As the study region consists of different types of soils such as medium black, redloam and laterite soils, the investigation makes use of the brightness temperature variations with reference to soil category in relation to soil wetness.