A connection between the tropical Pacific Ocean and the winter climate in the Asian-Pacific region
A connection between the tropical Pacific Ocean and the winter climate in the Asian-Pacific region
复制标题
热带太平洋与亚太地区冬季气候之间的联系
DOI：
10.1002/2014jd022324
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发表时间：
2015-01-27
影响因子：
4.4
通讯作者：
Bao, Qing
中科院分区：
文献类型：
--
作者：
Jia, XiaoJing;Wang, Su;Bao, Qing
利用1948 - 2008年的观测资料和线性斜压模式（LBM），研究了热带太平洋海温（SST）异常对亚太地区冬季平均气温（SAT）的影响。利用北方半球500 hPa高度场（Z500）与热带太平洋海温场（SST）的奇异值分解（SVD）分析，得到了与热带太平洋SST相关的大尺度大气型。重点是第二对SVD模式（SVD 2），它在Z500领域与北大西洋部门的北极涛动有一些相似之处，可以影响亚太地区更大范围内的SAT。在SVD 2为正值的冬季，亚洲大陆中高纬、北冰洋、印度洋和西副热带太平洋的SAT偏暖，而白令海峡附近的北太平洋异常偏冷，反之亦然。相关的地面大气环流的检查表明，一个积极的SVD 2倾向于移动西伯利亚高压南移和阿留申低压东移，导致亚洲大陆和北太平洋之间的异常弱气压梯度。在日本附近观测到异常的正海平面气压异常和亚洲大陆东海岸沿着的偏南风。与此同时，对流层中层东亚大槽减弱，东亚西风急流增强并北移。波活动通量的分析和理想化数值试验结果表明，热带西太平洋海温强迫对SVD 2的影响是可能的。
The impact of the tropical Pacific sea surface temperature (SST) anomaly on the winter mean surface air temperature (SAT) in the Asian-Pacific region is investigated during the period from 1948 to 2008 using both observations and a linear baroclinic model (LBM). A singular value decomposition (SVD) analysis is conducted between the 500hPa geopotential height (Z500) over the Northern Hemisphere and the SST over the tropical Pacific Ocean to obtain the large-scale atmospheric patterns related to tropical Pacific SST. Focus is given to the second pair of SVD mode (SVD2) which bears some similarities in the Z500 field to the Arctic Oscillation over the North Atlantic sector and can impact the SAT over a larger area of Asian-Pacific. In the winter of a positive SVD2 the SAT over the midlatitude to high-latitude Asian continent, the Arctic Ocean, the Indian Ocean, and the western subtropical Pacific Ocean tends to be warmer than normal, while the North Pacific Ocean around the Bering Strait is abnormally cold, and vice versa. Examination of the associated surface general circulation shows that a positive SVD2 tends to shift the Siberian High southward and the Aleutian Low eastward resulting in anomalous weak pressure gradient between the Asian continent the North Pacific. Anomalous positive sea level pressure anomalies around Japan and southerly wind along the east coast of the Asian continent are observed. At the same time, the East Asian trough at midtroposphere becomes weaker than normal and the East Asian westerly jet stream is increased in magnitudes and shifted northward. The analysis of the wave activity flux and result of idealized numerical experiments show a possible influence of the western tropical Pacific SST forcing on the SVD2.