Surface latent and sensible heat trigger flash drought events in India

Abstract

AbstractThe flash drought has gained widespread attention as a result of its rapid onset with severe impacts. However, a comprehensive assessment of different flash droughts based on various modulators is not carried out over India to date. Here, we attempt to answer the following research questions, (i) What is the status of different flash drought events due to soil moisture percentile drop (SMPD), standardized evaporative stress ratio (SESR), heat‐wave‐driven (HWD) and precipitation‐deficit‐driven (PDD) in India? (ii) How are these flash droughts distributed across India concerning occurrences, areal coverage, and persistence? (iii) What are the dominant factors that trigger different types of flash droughts? Lindeman, Merenda and Gold (LMG) method is used to examine the dominant factor. We find that PDD flash drought is noticed for the maximum time during 1959–2020. The SMPD flash drought occurrence is observed over northern parts of India. Mostly, Rabi and Zaid seasons experience the incidence of SMPD, SESR, and PDD flash drought conditions. However, HWD flash drought in more than 50% of the states is prominent in the Kharif season. The areal coverage shows a decreasing trend in the cases of SMPD, SESR, and PDD flash drought events. However, HWD flash drought condition has shown an increasing trend. The maximum percentage of SMPD and SESR flash drought events persisted for three to six pentads and five to eight pentads after the onset, respectively. For HWD and PDD flash droughts, most of the events last only for one to two pentads. The sensible heat flux and latent heat flux are responsible for triggering the flash drought events over most of parts in India.