The influence of Southern Hemisphere sea-ice extent on the latitude of the mid-latitude jet stream
The influence of Southern Hemisphere sea-ice extent on the latitude of the mid-latitude jet stream
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DOI：
10.1029/2011gl048056
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发表时间：
2011-08-04
影响因子：
5.2
通讯作者：
England, M. H.
中科院分区：
文献类型：
--
作者：
Kidston, J.;Taschetto, A. S.;England, M. H.
一个具有指定海冰和海面温度的大气环流模式被用来检验大气环流对南半球海冰范围变化的敏感性。进行实验的海冰边缘扩大或收缩7度的纬度相比，它的位置在控制运行。实验表明，海冰边缘的纬度影响南半球中纬度急流的纬度，但大气响应的幅度主要取决于海冰异常的位置和季节性。在冷季，当海冰范围增加时，中纬度急流显著地向极地移动，但当海冰范围减少时，中纬度急流的响应很小。在温暖的季节，无论海冰边缘是伸展还是收缩，急流都不会发生明显的变化。大气响应不对称的原因与海冰异常对近地面斜压带纬向温度梯度的影响程度有关。结果表明：1）任何未来南极海冰的减少都不太可能对南半球中纬度环流产生深远的影响; 2）海冰变率对季节预测的有用性仅限于寒冷季节和海冰范围增加的情况。引文：Kidston，J.，A. S. Taschetto，D. W. J. Thompson和M. H.英格兰（2011年），南半球海冰范围对中纬度急流纬度的影响，地球物理学。保留信函：38，L15804，doi：10.1029/2011GL048056。
An atmospheric general circulation model with prescribed sea-ice and sea-surface temperatures is used to examine the sensitivity of the atmospheric circulation to changes in sea-ice extent in the Southern Hemisphere. Experiments are conducted where the sea-ice edge is expanded or contracted by 7 degrees of latitude compared with its position in a control run. The experiments suggest that the latitude of the sea-ice edge influences the latitude of the Southern Hemisphere mid-latitude jet stream, but that the amplitude of the atmospheric response depends critically on the location and seasonality of the sea-ice anomalies. During the cold season, the mid-latitude jet shifts significantly poleward when the sea-ice extent is increased, but exhibits very little response when the sea-ice extent is decreased. During the warm season, the jet does not shift significantly regardless of whether the sea-ice edge is extended or contracted. The cause of the asymmetry in the atmospheric response relates to the extent to which the sea-ice anomalies affect meridional temperature gradients in the near-surface baroclinic zone. The results suggest that 1) any future decreases in Antarctic sea-ice are unlikely to have a profound effect on the Southern Hemisphere mid-latitude circulation; and 2) the usefulness of sea-ice variability for seasonal prediction is limited to the cold season and to the case of increases in sea-ice extent. Citation: Kidston, J., A. S. Taschetto, D. W. J. Thompson, and M. H. England (2011), The influence of Southern Hemisphere sea-ice extent on the latitude of the mid-latitude jet stream, Geophys. Res. Lett., 38, L15804, doi:10.1029/2011GL048056.