This study aims to explore the changing characteristics and mechanisms of the frequency of extreme compound humid-heat events in the Yangtze-Huai River Basin during summer over recent decades. The results indicate a high frequency of these events, with significant interannual variability. Further analysis identifies the summer North Atlantic Oscillation (NAO) as a key driver of changes in the occurrence of extreme compound humid-heat events in the region. The NAO influences the atmospheric circulation over the Yangtze-Huai River Basin through Rossby wave propagation, with upper-level anomalous high pressure favoring heat extremes and lower-level anticyclonic circulation enhancing moisture conditions. Moreover, previous studies have shown that sea surface temperatures in the Northwest Pacific and tropical Western Pacific are closely linked to the variability of these events. This study highlights that the combined influence of the summer NAO and sea surface temperatures in the Northwest Pacific and tropical Western Pacific contributes approximately 41% to the frequency of extreme compound humid-heat events in the Yangtze-Huai River Basin.
 

NAO, teleconnection, humid-hot events