Investigating rainfall trend over India using the wavelet technique

Abstract

In this paper, using the wavelet technique we analysed rainfall behaviour in the country across different agro-climatic zones over a century. Findings indicate that at the national level there is no significant trend in rainfall in the long run, but there are pockets of change in the rainfall pattern. There was a significant increase in the rainfall in the arid zone, whereas in the humid, semi-arid tropics and semi-arid temperate zones the trend was downward but insignificant. The behaviour of rainfall was different during this period. Except in the arid zone, we find a similar trend in other zones - increasing initially, tapering off in the middle and then declining but with some difference in time intervals. In the arid zone, the behaviour of rainfall had been erratic. In the short run, the direction of change in trend remains the same as in the long run but the change is statistically significant.