Climate Prediction and Outlook in China for the Flood Season 2023

In March 2023, the Annual Symposium on China Climate Prediction for summer (June–August) was held at the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences. Under the background of a transition from three consecutive La Niña years to El Niño development in the next four to six months, climate anomalies in China for summer 2023 are predicted based on the results of various numerical and statistical models developed by the IAP. It has been predicted that in the 2023 flood season (June–August), seasonally averaged precipitation slightly exceeding the normal precipitation might occur in the northern and eastern parts of Northeast China, most parts of North China, middle and lower reaches of the Yellow River, Yellow River and Huaihe River basins, southeast coastal region of China, central Northwest China, western parts of Xinjiang and Tibet, and central part of Southwest China. Particularly, rainfall exceeding 20%–50% of its normal occurrence is expected in the northern and eastern parts of Northeast China and the Yellow River and Huaihe River basins, implying a high possibility of local flooding disasters. In contrast, other parts of China, including the middle and lower reaches of the Yangtze River, central and eastern Inner Mongolia, and the northern part of Xinjiang, may experience drier than normal conditions in the coming summer, and the amount of precipitation might be reduced by 20% to 50% in these regions. Furthermore, the number of landing typhoons may be close to normal this summer. Due to the uncertainty of El Niño/Southern Oscillation evolution and limited ability to predict intraseasonal variations of warm pool convection and mid-high latitude atmospheric circulations, this climate prediction for the 2023 flood season is uncertain to some extent. The authors will conduct supplementary forecasts based on the observed variations of atmospheric and oceanic processes in the late spring and early summer of 2023.