Author(s): Vikas Poonia

Linked Author(s): VIKAS POONIA

Keywords: Ridity index; Flash drought; Intensification rate; Soil moisture; Triggers

Abstract: Quick onset and rapid intensification of drought, often known as “Flash Droughts (FDs)” have gathered significant attention in the recent past due to substantial consequences for water sources, ecosystems, and agriculture. The influence of FDs on society can vary depending on numerous factors like their frequency, intensification rate, and mean severity. However, these aspects are not yet well comprehended, particularly concerning India, and remain unclear. In this research, a novel method was developed to quantitatively establish the definition of FD using the Aridity Index (AI). This innovative approach was then applied to analyze the spatiotemporal features, including trends, and the factors that trigger FDs in 25 river basins throughout India from 1981 to 2021. During the study, the hydrometeorological conditions were thoroughly examined, encompassing precipitation anomalies, soil moisture percentiles, vapor pressure deficit, and temperature anomalies at different stages of flash drought. Also, we investigated FD impact on the terrestrial ecosystem. The findings indicate that FDs characterized by rapid intensification are more prevalent in humid regions as opposed to semi-arid and sub-humid regions. Moreover, the study reveals that both temperature and precipitation play crucial roles as primary triggers of FDs across a substantial portion of the research area. In specific regions, such as the Western Ghats and northeast India, the individual influences of precipitation and soil moisture act as triggers for FDs. Furthermore, atmospheric aridity can create conditions that are favorable for the occurrence of FDs. Further, a serious decrease in Water Use Efficiency (WUE) and underlying WUE is also observed over some parts of Southern India and Ganga river basin, which indicates the non-resilient nature of the ecosystem towards flash drought conditions. The findings will provide valuable insights to policymakers, enabling them to build effective policies to mitigate the repercussions of FDs on agriculture and water resources in India.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1800-cd

Year: 2025