Effects of extreme drought events on vegetation activity from the perspectives of meteorological and soil droughts in southwestern China

Fengxian Huang; Lulu Liu; Jiangbo Gao; Ziying Yin; Yibo Zhang; Yuan Jiang; Liyuan Zuo; Wenguo Fang

doi:10.1016/j.scitotenv.2023.166562

Effects of extreme drought events on vegetation activity from the perspectives of meteorological and soil droughts in southwestern China

Sci Total Environ. 2023 Dec 10:903:166562. doi: 10.1016/j.scitotenv.2023.166562. Epub 2023 Aug 24.

Authors

Fengxian Huang¹, Lulu Liu², Jiangbo Gao³, Ziying Yin⁴, Yibo Zhang¹, Yuan Jiang¹, Liyuan Zuo¹, Wenguo Fang⁵

Affiliations

¹ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
³ Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Academy of Plateau Science and Sustainability, People's Government of Qinghai Province & Beijing Normal University, Qinghai Normal University, Xining 810008, China. Electronic address: gaojiangbo@igsnrr.ac.cn.
⁴ China University of Geosciences (Beijing), Beijing 100083, China.
⁵ School of Geographic Science, Qinghai Normal University, Xining 810016, China.

PMID: 37633390
DOI: 10.1016/j.scitotenv.2023.166562

Abstract

Under climate warming, extreme drought events (EDEs) in southwestern China have become more frequent and severe and have had significant impacts on vegetation growth. Clarifying the influence of soil and meteorological droughts on the vegetation photosynthetic rate (PHR) and respiration rate (RER) can help policymakers to anticipate the impacts of drought on vegetation and take measures to reduce losses. In this study, the frequency and features of EDEs from 1990 to 2021 were analyzed using the standardized precipitation evapotranspiration index, and the longest-lasting and most severe EDE was chosen to assess the effects of drought on vegetation activity. Then, a land surface model was used to simulate the vegetation PHR and RER. Finally, the effects of the EDE on the vegetation PHR and RER were analyzed from the perspectives of soil and meteorological droughts. The results revealed that from 1990 to 2021, a total of 11 EDEs were observed in southwestern China, and the longest-lasting and most severe EDE occurred in 2009-2010 (EDE2009/2010). EDE2009/2010 significantly reduced the monthly mean PHR and RER by 9.82 g C m^-2 month^-1 and 0.80 g C m^-2 month^-1, respectively, causing a cumulative reduction of approximately 5.61 × 10¹³ g C. Soil and meteorological droughts had a driving force of 39 % on the PHR changes and an explanatory force of 42 % on the RER reduction. In particular, the soil drought had an average explanatory force of 25 % on the PHR and made a contribution of 24 % to the RER. The drought affected different types of vegetation differently, and crops were more susceptible than grassland and forests on the monthly time scale. The vegetation exhibited resilience to drought, returning to normal PHR and RER levels 2 months after the end of EDE2009/2010. This research contributes to understanding and predicting the impact of EDEs on vegetation growth in southwestern China.

Keywords: Common land model; Extreme drought event; Southwestern China; Vegetation activity.