Spatio-Temporal Trends and Projections of Climate Indices in the Banas River Basin, India

Abstract

The objective of the paper is to understand the historical and future climate change situation using 19 extreme climatic indices of daily precipitation and temperature (maximum and minimum) in the Banas River Basin of Rajasthan, India. For this study, both historical (1971–2013) and future period (2021–2050) data of precipitation and temperature are used to calculate the climate indices using the RClimDex tool. For the future period, ensemble data of precipitation and temperature from three Coordinated Regional Climate Downscaling Experiment South Asia (CORDEX-SA) climate experiments (CNRM-CM5, CCSM4 and MPI-ESM-LR) are used to predict the change in climatic indices. The test for significance was applied to all the indices for two historical periods (1971–2003 and 1981–2013) by using the Mann-Kendall method. The result shows the significant increase in the annual number of warm days and warm nights, whereas there is a decreasing trend in the annual number of cool days and cool nights. The significant decrease in the total annual precipitation (PRCPTOT) in two historical periods is observed. The Consecutive Dry Days (CDD) indicator shows an increasing trend for the past period and predicts the same for the future period over the basin. In the case of Number of heavy precipitation days (R10) and Number of very heavy precipitation days (R20) indices, there is a decreasing trend in the basin. In the case of temperature indices, there is a rise in temperature for most of the indices, but change is more in the lower basin as compared to the upper basin. Increase in consecutive dry days is also more prominent in the upper basin.