Sub-division wise probabilistic variability and extreme rainfall analysis of the Indian summer monsoon rainfall

Statistical analysis based on past data on probability of normal/excess rainfall, the probable future rainfall for smaller areas at different stages of the monsoon period will serve as an appropriate information system for efficient management of available surface water resource at the state and the national levels. In this paper the author have made an attempt in that direction and have brought out some important features of the monsoon rainfall. It is found that the probability of monthly rainfall becoming normal or excess is high in maximum number of sub-divisions in July and August and is least in September. It is further observed that the normality of rainfall as highly probable to the north of the monsoon trough in July and that to the south of the trough in August besides the west coast. The rainfall extreme values over a long period will be useful in determining the minimum assured and maximum probable future rainfall at different stages of the monsoon period. These information will be valuable to decision makers, managers etc. in their decision making process on real time basis.