The Annular Response to Tropical Pacific SST Forcing
The Annular Response to Tropical Pacific SST Forcing
复制标题
DOI：
10.1175/jcli3668.1
复制
发表时间：
2006-05
影响因子：
4.9
通讯作者：
Shuanglin Li;M. Hoerling;Shiling Peng;K. Weickmann
中科院分区：
文献类型：
--
作者：
Shuanglin Li;M. Hoerling;Shiling Peng;K. Weickmann
北半球冬季高度变率的主型表现为环状结构，这种结构与热带西太平洋加热有关。为了探索热带太平洋海温变化是否能激发这种模式，我们使用了一个耦合到平板混合层海洋的大气环流模式。利用赤道不同经度的理想化海温异常进行了集合试验。结果表明，西太平洋海温异常和东太平洋海温异常分别导致了两种不同的响应模式，一种是投射在环型上的半球型，另一种是局限于太平洋-北美地区的经向拱形型。热带外海气耦合增强了热带西太平洋海温异常响应的环状分量。基于线性动力模式的诊断表明，这两个响应主要是由瞬变涡动强迫维持的。在这两种情况下，模式的瞬变涡流强迫响应都有一个最大值。
Abstract The leading pattern of Northern Hemisphere winter height variability exhibits an annular structure, one related to tropical west Pacific heating. To explore whether this pattern can be excited by tropical Pacific SST variations, an atmospheric general circulation model coupled to a slab mixed layer ocean is employed. Ensemble experiments with an idealized SST anomaly centered at different longitudes on the equator are conducted. The results reveal two different response patterns—a hemispheric pattern projecting on the annular mode and a meridionally arched pattern confined to the Pacific–North American sector, induced by the SST anomaly in the west and the east Pacific, respectively. Extratropical air–sea coupling enhances the annular component of response to the tropical west Pacific SST anomalies. A diagnosis based on linear dynamical models suggests that the two responses are primarily maintained by transient eddy forcing. In both cases, the model transient eddy forcing response has a maximum ...