2023年春季我国气候异常特征及成因分析  

Features and Possible Causes of Abnormal Climateover China in Spring 2023

作　　者：龚振淞[1] 丁婷[1] GONG Zhensong;DING Ting(Key Laboratory for Climate Prediction Studies,National Climate Centre,CMA,Beijing 100081)

机构地区：[1]国家气候中心,中国气象局气候研究开放实验室,北京100081

出　　处：《气象》2023年第10期1267-1276,共10页Meteorological Monthly

基　　金：国家重点研发计划(2022YFF0801604);国家重点研发计划(2018YFC1505603);国家自然科学基金项目(42175048、42175078);国家气候中心能源气候服务团队建设项目(NCCCXTD003)共同资助。

摘　　要：2023年春季(3—5月),全国平均气温为11.5℃,为1961年以来历史同期第七高。除新疆、西北地区西部、西藏等地气温偏低外,我国大部分地区气温均偏高。全国平均降水量为132.7 mm,较常年同期偏少7.4%。降水呈现“北多南少”的特征,华北、黄淮及青藏高原等地降水偏多,东北、江南东部、华南和西南地区降水显著偏少。在对流层中层,春季亚欧中高纬度呈现“两脊一槽”分布,乌拉尔山地区为正高度距平中心,贝加尔湖至巴尔喀什湖为高度场负距平中心,而东北亚上空为位势高度场正异常;西太平洋副热带高压强度较常年偏弱;在对流层低层,热带西太平洋地区维持异常气旋性环流,其以北则为异常反气旋性环流。2023年春季东北亚高压脊指数为1.7,超过1个标准差,为1961年以来第四强,其异常偏强有利于我国北方降水偏多。长江以北地区受反气旋环流影响,异常偏东南风强盛,有利于将西北太平洋的暖湿水汽输送至我国北方地区。赤道中东太平洋自2021年9月开始一次弱La Ni?a事件,该事件一直持续至2023年3月结束,4月赤道中东太平洋海温开始转为暖水位相。2023年春季我国北方降水异常偏多受到赤道中东太平洋海温演变的影响,合成分析表明,在海温由冷转暖的春季,欧亚中纬度地区易出现“两脊一槽”的环流异常分布型,中西路冷空气南下影响我国,同时东亚上空反气旋式环流使得我国北方地区受异常东南风控制,西北太平洋水汽向北输送偏强,为北方地区的降水提供有利条件。In the springtime(March to May,MAM)of 2023,the mean temperature in China was 11.5℃,the seventh highest in history since 1961.The temperature in most of China was higher than normal except that in Xinjiang,the western part of Northwest China and Tibet was lower than normal.The national average precipitation was 132.7 mm,which is 7.4%less than normal.The precipitation showed a feature of“more in the north and less in the south”,with more precipitation in North China,Huanghuai Region and Qinghai-Tibeteau Plateau but significantly less in Northeast China,the eastern part of the region south the Yangtze River,South China,and Southwest China.In the spring(MAM)of 2023,a“two ridges and one trough”circulation was found to be distributed in the middle and high latitudes of Eurasia.In the middle troposphere,the positive height anomaly center was at the Ural Mountains area,the negative height anomaly center was from the Lake Baikal to Lake Balkhash area,and the geopotential height field was posi-tive anomaly over Northeast Asia.The western Pacific subtropical high was weaker than normal.In the lower troposphere,an abnormal cyclonic circulation maintained in the tropical western Pacific,while in its north there was an abnormal anticyclone circulation.The high ridge index in Northeast Asia in MAM 2023 was 1.7,exceeding one standard deviation.It is the fourth highest index since 1961,and is favorable for more precipitation in northern China.Affected by the anticyclone circulation,the area to the north of the Yangtze River had an abnormally strong southeasterly wind,which was conducive to the transport of the warm and wet water vapor from the Northwest Pacific to the northern region of China.A weak La Ni a event began in September 2021 in the equatorial central and eastern Pacific and lasted until March 2023.In April 2023,the sea surface temperature(SST)in the equatorial central and eastern Pacific began to shift to a warmer phase.In MAM 2023,precipitation in northern China was affected by the evolution of SST in the e

关 键 词：春季气候异常 La Ni?a事件 水汽输送 北方降水 

分 类 号：P461[天文地球—大气科学及气象学]