Circulation and overturning in the eastern North Atlantic subpolar gyre
Circulation and overturning in the eastern North Atlantic subpolar gyre
复制标题
北大西洋东部副极地环流的环流和翻转
DOI：
10.1016/j.pocean.2022.102884
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发表时间：
2022
影响因子：
4.1
通讯作者：
Li, F.
中科院分区：
文献类型：
--
作者：
Koman, G.;Johns, W.E.;Houk, A.;Houpert, L.;Li, F.
这项研究描述了对冰岛盆地北大西洋洋流的新运输估计，并利用这些结果与其他同期测量结果来确定北大西洋东部副极地环流的质量和翻转预算。作为副极地北大西洋翻转计划 (OSNAP) 的一部分，北大西洋洋流的估计是使用跨越冰岛盆地的三个全深度动态高度系泊装置确定的，并由 Argo 和卫星测高数据进行补充。与冰岛-苏格兰海岭交换的历史估计一起，来自罗卡尔海槽和罗卡尔-哈顿浅滩地区的额外 OSNAP 结果被用来计算东部副极地环流广大地区不同密度层的运输预算。结果表明，13–14 Sv 的北大西洋洋流 (σθ< 27.8 kg m−3) 通过 23.5°W 附近的一次斜压流和 26°W 附近的次生准正压流向北流入冰岛盆地中部。结合在罗卡尔-哈顿地区观测到的向北流动，我们得出结论，大西洋经向翻转环流上肢的 19-20 Sv (σθ< 27.56 kg m−3) 流入该区域，其中近 40% (7.3 Sv) 主要通过大气冷却的渐进水团改变而转化为下肢。这占大西洋经向翻转环流强度的近一半，该环流由从格陵兰岛延伸到苏格兰的整个盆地的整个 OSNAP 阵列定义。
This study describes new transport estimates of the North Atlantic Current in the Iceland Basin, and uses these results along with other contemporaneous measurements to determine mass and overturning budgets for the eastern North Atlantic subpolar gyre. As part of the Overturning in the Subpolar North Atlantic Program (OSNAP), estimates of the North Atlantic Current are determined using three full-depth dynamic height moorings spanning the Iceland Basin and are supplemented by Argo and satellite altimetry data. Along with historical estimates of the exchanges over the Iceland-Scotland Ridge, additional OSNAP results from the Rockall Trough and Rockall-Hatton Bank regions are used to calculate transport budgets in different density layers over a broad portion of the eastern subpolar gyre. Results show that 13–14 Sv of the North Atlantic Current (σθ< 27.8 kg m−3) flow northward into the middle of the Iceland Basin through a primary baroclinic flow near 23.5°W and a secondary quasi-barotropic flow near 26°W. Together with the observed northward flow in the Rockall-Hatton area, we conclude that 19–20 Sv of the upper limb of the Atlantic Meridional Overturning Circulation (σθ< 27.56 kg m−3) flows into the region where nearly 40 % of it (7.3 Sv) is converted into the lower limb primarily through progressive water mass modification from atmospheric cooling. This accounts for nearly half of the strength of Atlantic Meridional Overturning Circulation defined by the full OSNAP array extending across the basin from Greenland to Scotland.