Assessment Of Climate Change On The Extreme Precipitation In Upper Indus Basin

Abstract:

Extreme precipitation events from the western disturbances have significant impacts on the water management and ecosystem services in the Upper Indus basin, a part of the Hindukush Himalayan region. Further, there are changes in the duration, intensity, spatial extent and frequency of extreme events due to climate change. In this domain, a few studies have assessed the impact of climate change in the study area with limited data. There will be high uncertainty in the outcomes obtained from the investigation of extreme events with limited data. Therefore, a comprehensive analysis of extreme precipitation events from western disturbances considering high resolution with long-term data is required in the study area. Accordingly, In the present study, RX1day and RX5day ETCCDI Indices are calculated for every year, and non-parametric tests (Mann-Kendall, Innovative trend approach and Sen slope) are applied to detect the changes in the monthly precipitation during the winter season for the period 1901-2019. Further, the correlation between extreme precipitation and climate indices (Nino 3.4 and NAO) is explored to quantify the influence of ENSO and western disturbances on extreme precipitation. The findings of the present study reveal the northwest region has an increasing trend in RX1day extreme precipitation of 1.85 mm per decade in December, and the rate has amplified due to the effect of western disturbances in January and February. Also, the pattern of RX5day extreme precipitation is consistent in January and February. In recent decades, the northwest region of the upper Indus basin had faced more extreme events with severe impacts due to western disturbances, and outcomes from the study can improve the understanding of extreme events.