Comprehensive analysis of characteristics of dry–wet events and their transitions in Uttar Pradesh, India

Abstract

Understanding the occurrence and characteristics of dry and wet events is crucial for effective disaster prevention, resource management, and risk reduction in vulnerable regions. This study analyzed the spatiotemporal patterns of dry–wet events and their transition characteristics in Uttar Pradesh, India. The standardized precipitation evapotranspiration index (SPEI) at a monthly timescale was utilized to identify hotspot regions vulnerable to concurrent and frequent dry and wet events and their transitions. The severity, duration, and intensity of dry and wet events were characterized with the run theory over SPEI time series data from 18 synoptic stations in Uttar Pradesh over 48 years (1971–2018), sourced from the Indian Institute of Tropical Meteorology and the India Meteorological Department. Multiple assessment methods were utilized to examine the interaction of these extreme events, considering characteristics such as wet–dry ratio, average transition time, and rapid transition times from wet to dry events and from dry to wet events. Average wet durations ranged from 1.27 to 1.58 months, and average dry durations ranged from 1.29 to 1.82 months. Rapid transition times from dry to wet events ranged from 2.5 to 4.1 months, and those for wet-to-dry events ranged from 2.1 to 5.3 months. The eastern region experienced a significantly high number of dry events, while the western and Bundelkhand regions experienced more intense dry events. In contrast, the eastern region had intense wet events. This research on the occurrence of dry–wet events and their transitions can provide valuable insights for government decision-making and disaster prevention and reduction efforts. © 2024 Hohai University