Are the Near-Antarctic Easterly Winds Weakening in Response to Enhancement of the Southern Annular Mode?
Are the Near-Antarctic Easterly Winds Weakening in Response to Enhancement of the Southern Annular Mode?
复制标题
近南极东风减弱是否会因南环模增强而减弱？
DOI：
10.1175/jcli-d-18-0402.1
复制
发表时间：
2019
影响因子：
4.9
通讯作者：
A. Stewart
中科院分区：
文献类型：
--
作者：
Julia E. Hazel;A. Stewart
以前的研究强调了南大洋环流对加强的、向极移动的西风带的敏感性，这与越来越积极的南环模态（SAM）有关。SAM的影响被假设为减弱南极边缘周围东风输入海洋的动量。使用ERA-Interim数据，作者表明，在过去的3 - 40年里，绕极平均东风应力并没有减弱，如果有的话，稍微加强了约7%。然而，东风的季节性却大幅增加，在夏季偏南的东风减弱，而在冬季则增强。在其他三个与南极气象观测结果相当的再分析产品中也发现了类似的东风季节性趋势。作者将冬季东风的加强与海岸和极地之间的压力梯度的增加联系起来。虽然总体东风强度的趋势很小，但季节周期的变化可能会减少夏季表层沃茨的向岸埃克曼输送，并使夏季更多温暖的绕极深水进入大陆架。近海岸风的季节性周期变化也可能影响海冰的季节性形成和输出、威德尔和罗斯环流强度的波动以及南极底层水从大陆架的季节性输出。
Previous studies have highlighted the sensitivity of the Southern Ocean circulation to the strengthening, poleward-shifting westerlies, associated with the increasingly positive southern annular mode (SAM). The impacts of the SAM have been hypothesized to weaken momentum input to the ocean from the easterly winds around the Antarctic margins. Using ERA-Interim data, the authors show that the circumpolar-averaged easterly wind stress has not weakened over the past 3–4 decades, and, if anything, has slightly strengthened by around 7%. However, there has been a substantial increase in the seasonality of the easterlies, with a weakening of the easterly winds during austral summer and a strengthening during winter. A similar trend in the seasonality of the easterlies is found in three other reanalysis products that compare favorably with Antarctic meteorological observations. The authors associate the strengthening of the easterly winds during winter with an increase in the pressure gradient between the coast and the pole. Although the trend in the overall easterly wind strength is small, the change in the seasonal cycle may be expected to reduce the shoreward Ekman transport of summer surface waters and also to admit more warm Circumpolar Deep Water to the continental shelf in summer. Changes in the seasonal cycle of the near-coastal winds may also project onto seasonal formation and export of sea ice, fluctuations in the strengths of the Weddell and Ross Gyres, and seasonal export of Antarctic Bottom Water from the continental shelf.
影响因子：
3.5
作者：
Langlais, Clothilde E.;Rintoul, Stephen R.;Zika, Jan D.
通讯作者：
Zika, Jan D.
根据六次重新分析得出的气候学和最近阿蒙森海西风的增加
DOI：
10.1002/joc.3473
发表时间：
2012
期刊：
International Journal of Climatology
影响因子：
--
作者：
Bracegirdle T
通讯作者：
Bracegirdle T