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气象:2021,47(7):880-892
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2020/2021年冬季中国气候冷暖转折成因分析
韩荣青,石柳,袁媛
(国家气候中心,中国气象局气候研究开放实验室,北京 100081)
Analysis on the Causes of Cold and Warm Transition in China During the Winter of 2020/2021
HAN Rongqing,SHI Liu,YUAN Yuan
(Laboratory of Climate Studies, National Climate Centre, CMA, Beijing 100081)
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投稿时间:2021-04-23    修订日期:2021-05-14
中文摘要: 2020/2021年冬季,我国气候“前冬冷干、后冬暖湿”特征明显,冷、暖两个阶段气温振幅极大,多地观测气温分别打破了建站以来的最低、最高纪录。前冬(2020年12月1日至2021年1月10日),全国大部地区气温偏低、降水偏少,而后冬(2021年1月13日至2月28日),全国大部地区转入明显偏暖期,且2月上旬开始我国北方地区降水增多,暖湿特征明显。分析发现,乌拉尔山阻塞高压、西伯利亚高压和东亚冬季风强度、极地冷空气主体位置以及西北太平洋副热带高压的强度和位置等均发生了转折性变化,这是导致我国冬季气候由冷干转为暖湿的直接原因。进一步分析表明:La Ni〖AKn~D〗a事件配合北极冰偏少和北大西洋中纬度暖流,符合启动前冬“暖北极、冷欧亚”效应的条件,导致前冬欧亚中高纬经向环流偏强、乌拉尔山阻塞高压发展、及西伯利亚高压和东亚冬季风偏强,致使我国出现干冷型气候;而后冬,北极平流层发生爆发性增温事件,导致北极涛动持续负位相,极涡主体偏向西半球,但同时乌拉尔山阻塞高压崩溃,东亚冬季风转弱,我国大范围回暖增温。
Abstract:During the winter of 2020/2021, the climate over China was characterized by “cold and dry” in the first half of winter and “warm and wet” in the latter half of winter. In the cold and warm two periods, the amplitude of surface air temperature (SAT) fluctuated extremely, and the observed daily SATs at many stations in China broke the lowest and highest records, respectively. From 1 December 2020 to 10 January 2021, it was cold and dry over most of China, but turned sharply to warm and wet condition during the period from 13 January to 28 February 2021. The overturning changes of the large-scale circulation systems, including the Ural blocking, Siberian high, East Asian winter monsoon (EAWM), the position of the polar cold air and the western Pacific subtropical high, provided the direct reason for the cold-warm transition in China during this winter. Further analysis shows that the La Ni〖AKn~D〗a event, coupled with the reduced Arctic ice and the warmer North Atlantic currents in the mid-latitudes, met the conditions for the “warm Arctic, cold Eurasian” effect in the earlier winter. They intensified the meridional circulation with stronger Ural blocking, Siberian high and EAWM, and further led to the cold and dry climate in China. In the latter half of winter, the Arctic experienced a sudden stratospheric warming event, favoring the long-lasting negative Arctic Oscillation. The main body of the polar vortex shifted to the Western Hemisphere, while at the same time, the Ural blocking collapsed and the EAWM weakened. As a result, the temperature in most parts of China suddenly increased to be above normal.
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基金项目:国家自然科学基金委-云南省政府联合基金(U1902209)、国家重点研发计划(2018YFC1505603、2018YFC1506001)、国家自然科学基金项目(41776039)和国家科技支撑计划(2015BAC03B04)共同资助
引用文本:
韩荣青,石柳,袁媛,2021.2020/2021年冬季中国气候冷暖转折成因分析[J].气象,47(7):880-892.
HAN Rongqing,SHI Liu,YUAN Yuan,2021.Analysis on the Causes of Cold and Warm Transition in China During the Winter of 2020/2021[J].Meteor Mon,47(7):880-892.