Spatio-temporal evolution of wet–dry event features and their transition across the Upper Jhelum Basin (UJB) in South Asia

Rubina Ansari,Giovanna Grossi

doi:10.5194/nhess-22-287-2022

Abstract

Abstract. The increasing rate of occurrence of extreme events (droughts and floods) and their rapid transition magnify the associated socio-economic impacts with respect to those caused by the individual event. Understanding of spatio-temporal evolution of wet–dry events collectively, their characteristics, and the transition (wet to dry and dry to wet) is therefore significant to identify and locate most vulnerable hotspots, providing the basis for the adaptation and mitigation measures. The Upper Jhelum Basin (UJB) in South Asia was selected as a case study, where the relevance of wet–dry events and their transition has not been assessed yet, despite clear evidence of climate change in the region. The standardized precipitation evapotranspiration index (SPEI) at the monthly timescale was applied to detect and characterize wet and dry events for the period 1981–2014. The results of temporal variations in SPEI showed a strong change in basin climatic features associated with El Niño–Southern Oscillation (ENSO) at the end of 1997, with the prevalence of wet and dry events before and after 1997 respectively. The results of spatial analysis show a higher susceptibility of the monsoon-dominated region towards wet events, with more intense events occurring in the eastern part, whereas a higher severity and duration are featured in the southwestern part of the basin. In contrast, the westerlies-dominated region was found to be the hotspot of dry events with higher duration, severity, and intensity. Moreover, the surrounding region of the Himalaya divide line and the monsoon-dominated part of the basin were found to be the hotspots of rapid wet–dry transition events.

Highlights

There is growing evidence that recent warming is leading to significant alteration in the hydrological cycle, exacerbating extreme weather events in general (Peterson et al, 2012) in many regions of the world
This study focuses on the short-timescale conditions to analyse frequent variations in climatic conditions and their interplay; more detailed analysis was carried out at the monthly timescale
This study attempts to investigate the spatiotemporal variations in wet–dry events collectively, their characteristics, and transition from wet-to-dry and dry-to-wet events during the period 1981–2014 in the Upper Jhelum Basin (UJB) in South Asia

Summary

Introduction

There is growing evidence that recent warming is leading to significant alteration in the hydrological cycle, exacerbating extreme weather events in general (Peterson et al, 2012) in many regions of the world Extreme weather events such as floods and droughts and their rapid successions (recurrent spells) during the past few decades have taken a heavy toll on both life and property. Such events can have large impacts on water availability, agriculture and food security, power production, and natural ecosystems (He et al, 2019; Sheffield and Wood, 2012). Basin, national, and regional scales already documented and acknowledged the vulnerability to climate change of that region (He and Sheffield, 2020; Zhao et al, 2020; Visser-Quinn et al, 2019; He et al, 2017)

Methods

Results

Conclusion