关键词: 高温干旱复合极端事件;气象干旱综合指数;综合风险评估;2022年长江流域干旱;

Abstract: In 2022,the severe compound high temperature and drought extreme events in the Yangtze River Basin have brought a significant impact on water resources, ecosystems, economy and society.Based on the daily meteorological observation data of Yangtze River Basin from 1961 to 2022 and meteorological drought composite index( MCI),the long-term trend and relationship among the high temperature, drought and compound extreme events in the Yangtze River Basin were analyzed, conducting an assessment using comprehensive risk index based on frequency, intensity, duration and affected area.The results showed that:(1) the eastern Sichuan Basin, the middle and lower reaches of the Yangtze River and its south were most impacted by compound high temperature and drought extreme events in 2022,had showed the significantly increasing trends of compound events risk.(2) Due to the combined effect of the increasing duration of local compound events and the increasing risk of compound event in the upstream, the hydrological drought risk around the middle and lower reaches of the Yangtze River may increase.(3) Under the background of climate warming, high temperature and compound extreme events were getting more serious, especially in the east of Sichuan Basin and the southeast of Yangtze River.The dramatically increasing high temperature events led to the booming compound event, and drought events related to high temperature were more likely to happen.In addition, the intensity of compound extreme events was mainly contributed by the intensity of high temperature extreme events in the upper and middle reaches after the late 1990s.(4) From the perspective of comprehensive risk, there are many concurrent years of severe high temperature extreme events over the upper, middle and lower reaches, and in two regions of which severe drought events often occur and develop.In June to October since 2000,high-risk compound high temperature and drought events spreading over the whole Yangtze River Basin had taken place in 2006,2013,2019 and 2022 respectively.The research results can provide support for the identification of the compound extreme events of high temperature and drought in the Yangtze River Basin.

Key words: compound high temperature and drought extreme events; meteorological drought composite index; assessment of comprehensive risk; drought in Yangtze River Basin of 2022;