Variability in Summer Monsoon Rainfall over Pune, a Leeward Side Station of Western Ghats in India

Abstract

The summer monsoon (June through September) accounts for 80% of the annual rainfall over India. It exhibits large variability in different space and time scales. Present study attempts analysis on variability in summer monsoon rainfall over Pune a lee side station of Western Ghats of India using data for the period 1901-2012. Rainfall anomalies over Pune examined during El Nino and La Nina years and their intensities show below (above) normal rainfall during El Nino (La Nina) years. Further magnitude of the rainfall anomalies decreases from strong to weak intensities of Nino events. Strong positive relation is found between rainfall and zonal and meridional components of wind at 850hPa over southern part of India and the Arabian Sea, whereas negative relationship is found over northwest India (correlation coefficient is significant at 5% level). It indicates that cyclonic circulation over the north Arabian Sea favours rainfall activities over Pune. During flood years, similar features are observed with strong cyclonic circulation at 850 hPa over the north Arabian Sea. Droughts are associated with weakening of westerlies over Pune.