Zhang Erya, Wang Qingzheng, Guan Qingyu, Yang Xinyue, Luo Haiping, Zhang Jun, Du Qinqin, Zhang Zepeng
Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Sci Total Environ. 2024 Apr 1;919:170878. doi: 10.1016/j.scitotenv.2024.170878. Epub 2024 Feb 13.
Climate changes and human activities have led to a rise of frequency and intensity of the global flash droughts, resulting in severe consequences for ecosystems, agriculture, and human societies. However, research dedicated to flash droughts in the dryland of western China is relatively limited, leaving their evolutionary characteristics and development processes of these phenomena unclear. To bridge this gap, this study analyzed the spatiotemporal characteristics of flash droughts in western China from 1981 to 2020, based on the standardized evapotranspiration stress index. Additionally, we investigated the development mechanisms by taking meteorological conditions and soil moisture into account. The findings revealed that the northern Qinghai-Tibet Plateau, western Qilian Mountains, and western and southern Loess Plateau are hotspots of flash droughts, characterized by rapid development rates. Across most of the study area, flash drought events persisted between 25 and 30 days. Adequate precipitation is necessary before the onset of flash droughts in western China, while water scarcity and high temperatures played crucial roles in driving the mid-stage of flash droughts. Within the context of the observed "warming and wetting" trend, the average flash droughts occurrence from 2011 to 2020 was approximately 16 % lower than that from 1981 to 1990, and there was a significant annual decrease in spatial coverage of 0.01 % per year. However, in the "wetting in west, drying in east" trend, the spatial coverage of flash droughts has shifted from a declining trend to an insignificant increasing trend since 2000 in the study area, with significant regional differences between the western and eastern regions. Over the past decade, flash droughts had once again intensified in the central Qinghai-Tibet Plateau and the Loess Plateau due to warming and fluctuating wetting trends, raising significant concerns for future ecosystem and agricultural water management in these regions.
气候变化和人类活动导致全球骤发干旱的频率和强度上升，给生态系统、农业和人类社会带来了严重后果。然而，针对中国西部干旱地区骤发干旱的研究相对有限，这些现象的演变特征和发展过程尚不清楚。为弥补这一差距，本研究基于标准化蒸散胁迫指数，分析了1981年至2020年中国西部骤发干旱的时空特征。此外，我们还考虑了气象条件和土壤湿度，研究了其发展机制。研究结果表明，青藏高原北部、祁连山西部以及黄土高原西部和南部是骤发干旱的热点地区，其特点是发展速度快。在研究区域的大部分地区，骤发干旱事件持续25至30天。在中国西部，骤发干旱发生前需要有充足的降水，而水资源短缺和高温在骤发干旱的中期起了关键作用。在观测到的“暖湿化”趋势背景下，2011年至2020年骤发干旱的平均发生次数比1981年至1990年减少了约16%，空间覆盖范围每年显著下降0.01%。然而，在“西湿东干”趋势下，自2000年以来，研究区域内骤发干旱的空间覆盖范围已从下降趋势转变为不显著的上升趋势，东西部地区存在显著的区域差异。在过去十年中，由于气候变暖和干湿波动趋势，青藏高原中部和黄土高原的骤发干旱再次加剧，这对这些地区未来的生态系统和农业水资源管理构成了重大担忧。
