Flash Droughts Identification Based on an Improved Framework and Their Contrasting Impacts on Vegetation Over the Loess Plateau, China

Abstract

Abstract Flash drought occurs in a short timescale and has more adverse impacts on society and ecosystems than regular drought. Considering flash drought as a special type of regular drought and identifying it by the rate of the first intensification period might ignore posterior intensification periods. To this end, we introduced the combinatorial decomposable flash drought identification framework (CDFDI) to identify flash drought from the perspective of regarding it as the subphase of drought and explore the characteristics and vegetation response of flash drought in the Loess Plateau (LP), China, where is prone to drought and its ecological environment is very fragile. The neffectiveness of the framework is evaluated through the comparison analysis with a preexisting identification method proposed by Li et al. (2020, https://doi.org/10.5194/essd-12-1217-2020). Results indicate that: (a) the CDFDI framework can better capture flash drought events than the Liu’s method in terms of time series and spatial patterns, its rationality was further demonstrated by the obvious latitudinal pattern of correlation between flash drought and normalized difference vegetation index (NDVI); (b) the correlation shows an southeast (positive) and northwest (negative) contrasting pattern in the LP; (c) such contrasting pattern was also found in the response time of GPP, which suggests a more rapid impact on vegetation of flash drought in the arid northwestern LP; and (d) flash drought shows an exacerbating trend across the LP under the background of climate warming and mainly concentrated in the southern part. In general, this study provides new insights on flash drought connotations in a changing environment.

Publication
Water Resources Research

Related