Variability and trend analysis in the extreme climatic conditions in Beas River Sub-Basin of the Western Himalayas: A geo-statistical and geospatial approach

Abstract

Global warming has triggered environmental and socio-economic impacts, particularly affecting climate-sensitive regions such as Beas River Sub-Basin (BRSB). Limited studies have been done on extreme climatic events (ECE) in BRSB; in such situation detailed analysis of these events is need of the hour. Therefore, 18 climatic extreme indices have been used to assess climate change over the BRSB during 1964–2023. The Pruned Exact Linear Time algorithm has been used to identify change point and to divide the entire period into two period as P1 (1964–1993) and P2 (1994–2023). Trend analysis is assessed using Modified Mann-Kendall test and Theil-Sen's slope estimator. Result shows a decreasing trend of −0.32 mm/year in mean annual precipitation (MAP) and an increasing trend of 0.022 °C/year in Tmax, 0.028 in Tmin and 0.026 in average temperature during 1964–2023. The MAP shows an increasing trend of 8.40 mm/year during P1 and a decreasing trend of −0.93 during P2. Result shows a significant increasing trend of 0.154 days/year in number of consecutive dry days, 0.145 mm/day in Rx1day, and 3.7 days/decade in R10mm during 1964–2023. Also, a significant increasing trend of 0.046 °C/year in TXx and an increasing trend of 0.031 °C/year in TNn during 1964–2023 in BRSB. The increasing atmospheric warming may accelerate extreme events like cloudburst and flash-floods which in turn may trigger other natural hazards such as landslides, droughts and soil erosion and may reduce agricultural productivity. These findings highlight increasing climatic variability in BRSB, emphasizing the need for climate resilience strategies to mitigate the impacts of ECE.