Blocking and Rossby Wave Breaking on the Dynamical Tropopause in the Southern Hemisphere
Blocking and Rossby Wave Breaking on the Dynamical Tropopause in the Southern Hemisphere
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DOI：
10.1175/jas3984.1
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发表时间：
2007-08
影响因子：
3.1
通讯作者：
P. Berrisford;B. Hoskins;E. Tyrlis
中科院分区：
文献类型：
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作者：
P. Berrisford;B. Hoskins;E. Tyrlis
利用−-40资料研究了南半球动力对流层顶上的Rossby波破裂。波浪破碎的指示是基于位温经向梯度的反转，持续的大尺度波浪破裂被认为是可能存在阻塞的强烈迹象。中纬度阻塞主要发生在太平洋冬季，东太平洋阻塞最强烈，夏季阻塞频率减弱，范围仅限于西太平洋。阻塞的年际变化很大。波破裂最常发生在极地急流的极地一侧，并且具有一些但不是全部阻塞的特征，因此它被称为高纬度阻塞。一般情况下，气旋波破裂发生在极地急流的极地一侧，反之则发生反气旋破裂。然而，至少在冬季，海浪在海面上破碎。
Abstract Rossby wave breaking on the dynamical tropopause in the Southern Hemisphere (the −2-PVU surface) is investigated using the ERA-40 dataset. The indication of wave breaking is based on reversal in the meridional gradient of potential temperature, and persistent large-scale wave breaking is taken as a strong indication that blocking may be present. Blocking in the midlatitudes is found to occur predominantly during wintertime in the Pacific and is most vigorous in the east Pacific, while during summertime, the frequency of blocking weakens and its extent becomes confined to the west Pacific. The interannual variability of blocking is found to be high. Wave breaking occurs most frequently on the poleward side of the polar jet and has some, but not all, of the signatures of blocking, so it is referred to as high-latitude blocking. In general, cyclonic wave breaking occurs on the poleward side of the polar jet, otherwise anticyclonic breaking occurs. However, at least in wintertime, wave breaking in th...