Diversity and Formation of Persistent Wet–Cold Compound Extreme Events in China ^※

Despite global warming, persistent wet–cold compound extreme events (PWCEs) during wintertime still occur frequently in China, causing significant disruption of human and social activities. However, their full range, precursors, and evolution characteristics remain unclear. In this study, 252 PWCEs in China during cold seasons from 1961 to 2023 are objectively identified and further classified into the South China (SC), Western China (WC), and Central China (CC) types. Although the frequency of PWCEs has decreased under global warming, they still exhibit high extremity, and the WC-type events even show an upward trend in intensity. The three types of PWCE events share a similar “north high–south low” meridional pattern over mid–high latitudes but demonstrate significantly different circulation evolution attributes and precursors: the SC type is dominantly driven by cold-air outbreak linked to the Baikal blocking–East Asian trough; the WC type is controlled by the zonal wave train along the South Asian subtropi-cal westerly jet; the CC type is embedded within a well-organized midlatitude great-circle wave train across Eurasia. Their associated moisture transports also show diverse pathways: the SC type primarily harvests moisture from the South China Sea, the WC type from the India–Burma trough, and the CC type from both the western North Pacific anticyclone and the South China Sea. The precursors for PWCEs originate mainly from the Madden–Julian Oscillation modulating the tropical circulation and moisture transports, especially for the WC and CC types. These findings highlight the diverse formation links and precursors underlying PWCEs in China, offering insights for improving subseasonal prediction of the compound extreme events in China.