洞庭湖流域复合干热事件时空变化和归因分析OA

Compound dry-hot events have caused severe socioeconomic losses to human society and the natural environment.Given the negative correlation between summer mean temperature and precipitation,we developed a Compound Dry-Hot Index(CDHI)based on the Copula method,which integrates the summer Standardized Precipitation Evapotranspiration Index(SPEI)and the Standardized Temperature Index(STI).Using CDHI combined with path analysis,the driving factors for changes of com-pound dry-hot intensity in the Dongting Lake Basin during summer from 1901 to 2022 were assessed,and their spatio-temporal characteristics were analyzed using gridded data.The results showed that:① A strong tail dependence existed between summer drought events and high temperature heatwave events represented by STI in the Dongting Lake Basin,which to some extent exacer-bated the compound dry-hot intensity in the northwestern and southern regions of the basin.② From 1962 to 2022,the affected area of severe compound dry-hot events,as characterized by CDHI,had shown a continuously expanding trend.③ Path analysis results indicated that the impact of rising summer mean temperature on the severity of compound dry-hot events in the basin has significantly intensified over the past 60 years,with its contribution rate being more prominent than that in the preceding 60-year period,suggesting a notable shift in the influence mechanism of warming effects on compound dry-hot events in recent decades.The findings not only contribute to improving risk assessment of compound extreme events but also provide a scientific basis for developing targeted climate change adaptation strategies.