2023年汛期气候趋势预测与展望

Climate Prediction and Outlook in China for the Flood Season

2023年3月,中国科学院大气物理研究所开展汛期(6~8月)全国气候趋势预测会商会。通过综合大气所各数值模式和统计模型的结果,在未来4~6个月热带中东太平洋从持续3年的La Niña事件转为异常偏暖状态的背景下,预计2023年汛期,东北的北部和东部、华北大部分地区、黄河中下游、黄淮流域、东南沿海、西北地区中部、新疆和西藏的西部、西南地区中部降水正常略偏多,其中东北的北部和东部以及黄淮流域降水偏多2~5成,可能发生局地洪涝灾害。全国其他大部分地区降水正常略偏少,其中长江中下游地区、河套北部至内蒙古中东部、新疆北部降水偏少2~5成,可能发生阶段性高温热浪。预计今年夏季登陆台风数量接近正常。由于未来ENSO的演变趋势、西太平洋暖池对流的异常变化以及中高纬度环流异常的季节内变化等诸多因素都具有不确定性,因此此次汛期降水预测结果也存在一定的不确定性。将根据2023年春末、夏初大气环流和海洋等因子的实际演变趋势,做进一步补充订正预测。

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.