2021年华北雨季气候特征及华北降水偏多成因初探  

Climate Characteristics of Rainy Season and Causes for More Precipitation in North China in 2021

作　　者：赵琳[1] 孙林海[1] 竺夏英[1] 张永涛 崔童[1] 李威[1] 艾婉秀[1] 尹宜舟[1] Zhao Lin;Sun Linhai;Zhu Xiaying;Zhang Yongtao;Cui Tong;Li Wei;Ai Wanxiu;Yin Yizhou(National Climate Center,Beijing 100081,China;CMA·Henan Key Laboratory of Agrometeorological Support and Applied Technique,Zhengzhou 450003,China;Henan Climate Center,Zhengzhou 450003,China)

机构地区：[1]国家气候中心,北京100081 [2]中国气象局·河南省农业气象保障与应用技术重点实验室,郑州450003 [3]河南省气候中心,郑州450003

出　　处：《气象与环境科学》2022年第2期20-26,共7页Meteorological and Environmental Sciences

基　　金：国家自然科学基金面上基金(42175078);国家重点研发计划(2018YFC1501706);国家自然科学基金面上项目(41975088)。

摘　　要：根据近60年华北地区236站逐日降水量资料和2021年夏季NCEP再分析资料,对2021年中国华北雨季的气候特征及其成因进行分析。结果表明,2021年华北雨季于7月12日开始,较常年偏早6 d;于9月9日结束,较常年偏晚22 d;平均雨量为276.4 mm,较常年偏多103.2%;雨季长度为59 d,为1961年以来的第2长。2020年8月至2021年4月的拉尼娜事件是2021年华北雨季偏强的重要外因,也是最重要的年际预测信号;另外,2020年冬季和2021年春季青藏高原积雪偏少是2021年我国北方降水偏多的另一年际预测信号。而造成2021年华北雨季偏强的直接原因则是大气环流异常,500 hPa东亚中高纬呈现“东高西低”的距平环流分布,贝加尔湖至我国长江下游的大槽非常有利于冷空气的南下,850 hPa我国长江以北地区受到异常气旋环流东北侧的偏南风距平控制,给北方地区带来良好的水汽输送。冷暖空气在北方地区交汇,造成华北东部等地降水偏多。Based on the daily precipitation data of 236 stations over North China in the past 60 years and the NCEP reanalysis data in 2021,the climate features and causes for more precipitation in North China in 2021 are analyzed.The results show that the rainy season of North China in 2021 began on 12 July,six days earlier than normal,and ended on 9 September,22 days later than normal.The average rainfall was 276.4 mm,103.2%more than normal and the length of rainy season was 59 days,the second longest since 1961.The LA NIA event from August 2020 to April 2021 was a significant external cause of the heavy rainy season in 2021,and was also the most important interannual forecast signal.In addition,the less snow cover over the Tibetan Plateau from the winter 2020 to spring 2021 was another interannual forecast signal of the more precipitation in 2021 in northern China.However,the direct cause responsible for the 2021 heavy rainy season in North China was the abnormal atmospheric circulation.At 500 hPa,the middle and high latitudes of East Asia presented an anomalous circulation distribution of the“the high in the east and the low in the west”.The large trough from Lake Baikal to the lower reaches of the Yangtze River,China,was very favorable for the southward movement of the cold air,while the north of the Yangtze River in China was controlled by the southerly anomaly on the northeast side of the anomalous cyclone circulation at 850 hPa,which favored a better water vapor transport to the north.Finally,the cold and warm airs met in the northern China,resulting in more rainfall than normal in the east of North China and many other localities.

关 键 词：华北雨季 降水 气候特征 成因 

分 类 号：P468.024[天文地球—大气科学及气象学]