Analysis of increasing heavy rainfall activity over western India, particularly Gujarat state, in the past decade

Abstract

The study of spatial and temporal variations of rainfall during monsoon has been studied by many scientists. India receives about 80 % of total annual rain during the southwest summer monsoon season from June to September. The number of moderate rain days and low rain days averaged over whole of India have significantly decreased whereas the number of heavy rain days is found to have increased (Dash et al. 2009). However, the trends in heavy rainfall events are not uniform over central India. For example, Mohapatra and Mohanty (2005) have found that there is no significant trend in frequency of very heavy rainfall in recent years over Orissa. By using a daily rainfall data set, Goswami et al. (2006) have shown (i) significant rising trends in the frequency and the magnitude of extreme rain events and (ii) a significant decreasing trend in the frequency of moderate events over central India during the monsoon season from 1951 to 2000.