Variation characteristics of high-temperature and drought compound disasters in Liaoning Province based on Copula...

Under the backdrop of global climate change, the frequent occurrence of combined disasters of high temperature and drought poses severe challenges to food security, ecological environment, and sustainable socio-economic development. Based on the meteorological observation data from 1971 to 2024, we constructed an intensity index by combining the nested Copula model with the random forest algorithm, and analyzed the spatiotemporal variations, recurrence interval characteristics and intensity evolution law of compound high-temperature and drought disasters in Liaoning Province by coupling GIS technology. The results showed that the occurrence frequency of compound high-temperature and drought disasters presented a pattern of being high in the west and low in the east. The western region was a continuously expanding and intensifying high-frequency agglomeration area, while the eastern and coastal areas remained a stable low-frequency area for a long time. Compound high-temperature and drought disasters in Liaoning Province were dominated by short recurrence interval (0-2 years) events, which featured with high occurrence frequency and strong spatial agglomeration. The western region as the core high-incidence area. With the extension of the return period, the occurrence scope of disasters shrank sharply and the frequency decreased, and long recurrence interval events were only sporadically distributed in the western region. The intensity of single events experienced a phased evolution of weak occurrence-initial increase-rapid increase-maintenance-attenuation, peaking in the 1990s. The cumulative intensity gradually evolved from a pattern of single low-value agglomeration in the western region in the 1970s to a dual high-intensity agglomeration pattern in the western and central regions in the 2010s. The intensity of the core western region reached its peak at the end of the study period. In summary, the western region of Liaoning Province was the core affected area of compound high-temperature and drought disasters, and the disaster intensity showed an increasing trend. This study could provide a scientific basis for the formulation of disaster prevention and mitigation strategies and risk management in Liaoning Province.