Extreme Precipitation Probability over East China in Spring and Summer During the Decaying of Two Types of El Nino Events

Based on the surface-gridded daily precipitation dataset and the simulation results from the Coupled Model Intercomparison Project Phase 6 (CMIP6) models, this study investigates the variation of extreme precipitation probability over East China in spring and summer during the decaying year of East Pacific (EP)/Central Pacific (CP) El Nino events and explores possible influencing mechanisms. The results show that for the EP El Nino, in spring, the probability of extreme precipitation is much higher in the vast majority of East China. The anticyclonic water vapor transport in the Northwest Pacific and the higher temperature in East China jointly result in a large amount of water vapor converging and ascending in East China, which is conducive to extreme precipitation events in this region. In summer, the probability of extreme precipitation events decreases, but is still high in the Yangtze River Basin, corresponding to the weak and northerly anticyclone over the Northwest Pacific and the convergence and ascending of water vapor in the Yangtze River Basin. For the CP El Nino, the most obvious probability increase of extreme precipitation events appears over Northeast China and the Yangtze River Basin in spring. These regions are featured by positive geopotential height anomalies and strong northerly wind. Meanwhile, the temperature in Northeast China is slightly lower. In summer, the probability of extreme precipitation events in most areas significantly increases. The anomalous cold high-pressure center over the north of the South China Sea is notably strong, and the northwestern Pacific anticyclone expands to the west and the north. East China is mainly affected by the warm-wet southwesterly airflow, which is conducive to extreme precipitation events. The United States Geophysical Fluid Dynamics Laboratory model well represents the probability distribution of extreme precipitation events and the atmospheric circulation of the EP/CP El Nino. However, compared with observations, there are some biases, such as the higher probability of extreme precipitation in Central China in summer under the EP El Nino.