Validation of Satellite Rainfall Estimation in the Summer monsoon dominated area of the Hindu Kush Himalayan region

Weather events like intensive rainfall causing floods and flash floods result into loss of lives and properties whereas prolong drought can cause decline in agriculture production and loss of vegetation cover. Rainfall affects the lives and economies of majority of people where the populations are dependent on rain water for agriculture. With the existence of large unpopulated rugged terrain with limited number of observation hydro-meteorological stations, accurate rainfall estimation is a challenging task and the spatial distribution of the rain gauge is not sufficient to provide a detail outlook on highly temporal and spatial variable nature of rainfall that may be needed for applied stream flow modeling technique. In the present paper, the estimated 24 hours rainfall product developed by National Oceanic and Atmospheric Administration (NOAA) in a South Asian domain was validated with the observed rain gauge data on a daily basis for the monsoon period of 2002 to 2004. The result shows maximum negative bias and root mean square error (RMSE) in the heavy rainy days and Satellite Rainfall Estimation (SRE) overestimates the rain before monsoon and in rain shadow area. Qualitatively rainfall events in general match but quantitatively SRE and observed rain gauge product are vast difference. The study provides important input for the improvement of the SRE development algorithms. Further, incorporation of orographic effect in the algorithm is felt necessary before it should be implemented to the stream flow model for flood forecasting.