Trend and homogeneity test analysis for rainfall over a 121-year time period in the desert district of Western Rajasthan, India

Abstract

The Thar Desert receives very scarce and scanty rainfall; hence, water is given the top priority and importance in daily life. During the past decades, there has been a variation in the trend of the rainfall, climate, and other atmospheric conditions in the Jaisalmer district. An analytical study has been carried out to investigate this changing environmental phenomenon. Sixteen grids have been selected to study the trend and magnitude of the slope for rainfall using the MMK (Modified Mann–Kendall) test and Sen’s Slope estimator. Pettitt’s test, SNHT (Standard Normal Homogeneity Test), and Buishand’s test have been used to find trend change year in 121-year time series of rainfall. Mean annual rainfall for all grids shows positive values of Kendall’s tau and Sen’s Slope, which indicate that trend interpretation is rising, and test interpretation is increasing. Most of the results obtained from grids show the year ‘1992’ as the trend-changing year. A significant rise in mean annual rainfall has been noticed after the change of year in the study area. This type of study has not been conducted earlier in the region to identify the rainfall trend and change of year of trend. This study will help policymakers to take necessary action.