Spatio-temporal Analysis of Rainfall Distribution and Variability in the Twentieth Century, Over the Cauvery Basin, South India

Abstract

Knowledge on the spatial variability and temporal trends of mean rainfall is essential for efficient management of water resource and agriculture. We have analyzed the rainfall data of the Cauvery river basin, a larger river basin in Southern India which plays a significant role in agricultural development and consequently in the overall growth of Karnataka, Tamil Nadu, Pondicherry and some parts of Kerala. The analysis includes distribution, variability and trends in rainfall over the Cauvery basin during twentieth century (1901–2002). The impact of climate change on temporal and spatial patterns of rainfall over smaller spatial scales is clearly noticed in this analysis. It is also observed that the coefficient of variation shows significant fluctuations during the winter than other seasons. Long term changes in rainfall have been determined by. Significant decreasing trend in the winter rainfall and increasing trend in the post-monsoon season with insignificant levels have been inferred based on the Mann-Kendall rank statistics and linear trend. Overall, insignificant decrease in annual rainfall over the Cauvery river basin has observed during twentieth century.