2022年汛期气候趋势预测与展望

Climate Prediction and Outlook in China for the Flood Season 2022

中国是自然灾害频发的国家,气象灾害造成的损失占自然灾害造成损失的70%。2020年夏季出现超长梅雨期,长江和淮河发生洪水;2021年夏季,华北雨季开始早,结束晚,期间发生了“21·7”河南地区特大暴雨事件。这些气象灾害都对人民生命财产造成严重损失。因此,有必要提前对气候异常进行预测,以提高国家的防灾减灾能力。2022年3月,中国科学院大气物理研究所开展汛期(6~8月)的全国汛期气候趋势预测会商会。通过综合大气所各个数值模式和统计模型的结果,在未来4~6个月全球短期气候仍处在La Niña事件恢复到ENSO正常状态的背景下,预计2022年汛期(6~8月),东北东部和中部、华北大部分地区、黄河中下游、东南沿海、西北地区中部、西藏大部分地区、西南地区东部和云南大部分地区降水正常略偏多,其中环渤海湾地区降水偏多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,其中长江下游地区和新疆北部降水偏少2~5成。预计今年登陆台风数正常略偏多。由于未来ENSO的趋势演变具有一定的不确定性以及夏季降水受到中高纬大气环流季节内变化的影响,因此,此次汛期预测结果具有一定的不确定性。我们将根据2022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。

China is a country prone to natural catastrophes,and the losses generated by meteorological events account for 70%of all natural disaster losses.In the summer of 2020,the unusually long Meiyu period occurred,leading to heavy floods in the Yangtze River valley and Huaihe River basin.In the summer of 2021,the rainy season in North China began earlier and ended later than usual,during which the“21·7”torrential rain event occurred in Henan Province.All of these natural disasters have had terrible effects on the local economy and society.As a result,seasonal climate predictions are extremely significant.In March 2022,the Annual Symposium on China Climate Prediction for the summer season(June−August)was held at the Institute of Atmospheric Physics(IAP),Chinese Academy of Sciences(CAS).Climate anomalies in China for summer 2022 are expected based on the results of several numerical and statistical models of IAP against the background of a transition from a La Niña event to an El Niño/Southern Oscillation(ENSO)normal state in the next 4−6 months.During the flood season(June−August)2022,slightly more than normal seasonally averaged precipitation might occur in eastern and central parts of Northeast China,most parts of North China,the middle and lower reaches of the Yellow River,the southeast coastal region of China,central Northwest China,most parts of Tibet,the eastern part of Southwest China,and most parts of Yunnan Province.In particular,20%-50%above average may be forecast in the Bohai Bay area,meaning a high risk of local flooding disasters.In contrast,other portions of China may see drier than normal weather this summer,and the precipitation amount might be reduced by 20%-50%in the lower reaches of the Yangtze River and the northern part of Xinjiang.This summer’s landfall typhoon may be slightly more than normal.Due to the uncertainty of ENSO evolution and limited ability to predict intra-seasonal variations of mid-and high-latitude atmospheric circulations,these climate prediction results for flood season are uncertain to some extent.The authors will make additional estimates based on the observed fluctuations in atmospheric and oceanic processes in the late spring and early summer of 2022.