Influence of the Meridional Shifts of the Kuroshio and the Oyashio Extensions on the Atmospheric Circulation
Influence of the Meridional Shifts of the Kuroshio and the Oyashio Extensions on the Atmospheric Circulation
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DOI：
10.1175/2010jcli3731.1
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发表时间：
2011-02-01
影响因子：
4.9
通讯作者：
Alexander, Michael A.
中科院分区：
文献类型：
--
作者：
Frankignoul, Claude;Sennechael, Nathalie;Alexander, Michael A.
利用1982-2008年高分辨率月海温距平资料和1979-2007年历史海温资料，采用滞后回归分析方法，分析了黑潮延伸区（KE）和亲潮延伸区（OE）的纬向位移对大尺度大气环流的影响。信号是独立的ENSO遥相关，这是删除的季节性变化，不对称回归到前三个主成分的热带太平洋海温异常。对东太平洋锋纬向位移的响应是相当正压的，大致类似于北太平洋涛动/西太平洋模式的正相位，为向北的锋位移。在250 hPa上，对于一个典型的东太平洋漂移，其响应可达35 m，这是一个很强的敏感性，因为与之相关的海温距平为0.5 K。然而，振幅，而不是模式或统计意义，强烈依赖于滞后和假设的2个月的大气响应时间。在秋季和冬季，当锋面向南移动时，这种反应更强。对KE北移的响应主要包括以北太平洋西北部为中心的高压和半球遥相关。除堪察加半岛附近外，其响应也是相当正压的，在那里它随高度略微向西倾斜。典型的振幅是与OE偏移相关的振幅的一半。
The meridional shifts of the Oyashio Extension (OE) and of the Kuroshio Extension (KE), as derived from high-resolution monthly sea surface temperature (SST) anomalies in 1982-2008 and historical temperature profiles in 1979-2007, respectively, are shown based on lagged regression analysis to significantly influence the large-scale atmospheric circulation. The signals are independent from the ENSO teleconnections, which were removed by seasonally varying, asymmetric regression onto the first three principal components of the tropical Pacific SST anomalies. The response to the meridional shifts of the OE front is equivalent barotropic and broadly resembles the North Pacific Oscillation/western Pacific pattern in a positive phase for a northward frontal displacement. The response may reach 35 m at 250 hPa for a typical OE shift, a strong sensitivity since the associated SST anomaly is 0.5 K. However, the amplitude, but not the pattern or statistical significance, strongly depends on the lag and an assumed 2-month atmospheric response time. The response is stronger during fall and winter and when the front is displaced southward. The response to the northward KE shifts primarily consists of a high centered in the northwestern North Pacific and hemispheric teleconnections. The response is also equivalent barotropic, except near Kamchatka, where it tilts slightly westward with height. The typical amplitude is half as large as that associated with OE shifts.