Assessment of climate variability and trends in different physiographic zones of North Western Himalayas

Abstract

Himalaya – one of the pristine and ecologically fragile mountain ecosystem is highly vulnerable to any small changes in climatic system. Under changing climate conditions, assessing regional trends become more important owing to dependence of more than 1 billion people on Himalayas. To analyze the climatic trends and magnitude, this study utilized the long term meteorological data (1980–2022) for temperature and precipitation. Investigations were carried out for 11 meteorological stations located in different topographical zones of Jammu, Kashmir and Ladakh region. The non-parametric Mann–Kendall test was used for significance of trends in precipitation and temperature data on monthly, seasonal, and annual scales, while Sen’s non-parametric estimator of the slope was used to estimate the magnitude of trend. For T_Max, except Jammu plains (-0.018°C a^-1) all regions experienced increasing trend with annual rate of increase 0.018°C a^-1, 0.032oC a^-1 and 0.051°C a^-1 in Pir Panjal region, Kashmir valley and Ladakh region respectively. For annual T_Min, all four geographical regions and individual stations have observed an increase. Ladakh region observed highest rate of increase (0.070°C a^-1) which was significant followed by Pir Panjal region (0.048°C a^-1), Kashmir valley (0.013°C a^-1) and the lowest rate was observed in Jammu Plains (0.006°C a^-1). Precipitation revealed a general decreasing trend with large inter annual variability. Seasonally, T_Min has seen most significant changes across all topographical regions. Our results indicate that influence of Indian Summer Monsoon (ISM) was more towards the Jammu plains and its impact reduced towards Pir Panjal and Kashmir valley with increasing influence of Western Disturbances (WDs). Jammu plains received 75.8# precipitation from ISM while Kashmir valley received 72.4# precipitation from WDs. Shift in climatic variables could have serious environmental and socio-economic implications which can alter the regional ecological stability.