283-Regional Frequency Analysis of Rainfall in India under Climate Change Scenarios.

Abstract

Recently there is growth in scientific consensus that global climate is changing. In this scenario engineers are devoting their efforts to explore plausible implications of the climate change on water which is one of the most vulnerable resources of earth. In India, rainfall is the major source of water to river basins. Effective estimation of the magnitude and frequency of rainfall is necessary for hydrologic designs. However, often the available at-site information on rainfall is inadequate to arrive at reliable estimates. This necessitates the use of regional frequency analysis to pool adequate information from several locations in the region that are similar in terms of their hydro-meteorological characteristics. A few attempts have been made in the past three decades to identify homogeneous monsoon rainfall regions over India. However, the regions were not effectively validated. In this study, it is shown that the homogeneous monsoon regions that are in use by India Meteorological Department (IMD) are statistically heterogeneous. Subsequently, a novel regionalization procedure based on hydro-meteorological input is presented to form homogeneous rainfall regions in India. Following this, plausible implication of climate change on the delineated regions is assessed by using simulations from Canadian third Generation coupled General Circulation model. Results indicate that the proposed approach to regionalization is efficient in delineating homogeneous rainfall regions, and the future changes projected for the delineated homogeneous SMR regions are insignificant.