中国春季复合极端低温多雨事件的年代际变化及成因分析OA北大核心CSTPCD

Based on the daily minimum temperature data,precipitation data at 553 stations in China and ERA5 monthly reanalysis data from 1961 to 2020,the interdecadal variation characteristics and its possible causes of compound extreme cold and rainfall events in spring of China were explored.Results indicate that the compound extreme cold and rainfall events in spring exhibit a distribution pattern of more in the south and less in the north,with the highest frequency(more than 5 days per year on average)occurring in the Southwest and South China.The compound extreme cold and rainfall events in spring in the majority of regions in China have presented a decreasing trend in the past 60 years.In the late 1990s,there was a nationwide interdecadal mutation from more to less,with the most significant decreasing being in the monsoon region of southeastern China.Further analysis shows that the anomalous cyclonic circulation from northern China to the Bering Strait and the anomalous anticyclonic circulation over the northwest Pacific on the southeast of China are the two key circulation systems causing the interdecadal mutation.