Exploring Climate Variables and Drought Patterns: A Comprehensive Trend Analysis and Evaluation of Beas Basin in Western Himalaya

The complex topography of the Himalayan region makes it difficult to analyze its climatic variables over the region. The study has been carried out to identify the trends in climate variables and drought analysis over the Beas River basin in the western Himalayas. To understand the impact of changing climate on the Beas River basin, five downscaled global circulation models (GCMs) were used, namely BNU-ESM, Can-ESM2, CNRM CM5, MPI-ESM MR, and MPI-ESM LR. These GCMs were obtained for two representative concentration pathway (RCP) scenarios: 4.5, which represents the normal scenario, and 8.5, which represents the most extreme scenario for anticipated concentrations of carbon and greenhouse gases. The multi-model ensemble (MME) of these 5 GCMs were used to project rainfall and temperature. Further Innovative Trends Analysis (ITA) and modified Mann-Kendell (mMK) trend tests have been used for trend analysis at a 5% significance level. The drought pattern in the future timescale of the ensembled model is calculated using the Standardised Precipitation Index (SPI) for both RCPs. The ITA, Mann-Kendell, and Sen's slope trends showed decreased precipitation under RCP 4.5 in the Manali region and showed an increasing trend for the remaining locations under both scenarios. Furthermore, SPI values showed frequent droughts under both RCPs. The study outcomes will serve as a scientific foundation for the sustainability of water resources and agricultural output in arid inland regions vulnerable to changing climate.