Drought thresholds that impact vegetation reveal the divergent responses of vegetation growth to drought across China

作者：Mingze Sun, Xiangyi Li, Hao Xu, Kai Wang, Nazhakaiti Anniwaer, Songbai Hong · 发表于：Global Change Biology · 年份：2023 · DOI：10.1111/gcb.16998 · 被引用次数：96 · 研究领域：Hydrology and Drought Analysis、Plant Water Relations and Carbon Dynamics、Remote Sensing in Agriculture

Abstract Identifying droughts and accurately evaluating drought impacts on vegetation growth are crucial to understanding the terrestrial carbon balance across China. However, few studies have identified the critical drought thresholds that impact China's vegetation growth, leading to large uncertainty in assessing the ecological consequences of droughts. In this study, we utilize gridded surface soil moisture data and satellite‐observed normalized difference vegetation index (NDVI) to assess vegetation response to droughts in China during 2001–2018. Based on the nonlinear relationship between changing drought stress and the coincident anomalies of NDVI during the growing season, we derive the spatial patterns of satellite‐based drought thresholds ( T SM ) that impact vegetation growth in China via a framework for detecting drought thresholds combining the methods of feature extraction, coincidence analysis, and piecewise linear regression. The T SM values represent percentile‐based drought threshold levels, with smaller T SM values corresponding to more negative anomalies of soil moisture. On average, T SM is at the 8.7th percentile and detectable in 64.4% of China's vegetated lands, with lower values in North China and Jianghan Plain and higher values in the Inner Mongolia Plateau. Furthermore, T SM for forests is commonly lower than that for grasslands. We also find that agricultural irrigation modifies the drought thresholds for croplands in the Sichuan Basin. For future ...