Evolution of the Thermohaline Structure of One Agulhas Ring Reconstructed from Satellite Altimetry and Argo Floats
Evolution of the Thermohaline Structure of One Agulhas Ring Reconstructed from Satellite Altimetry and Argo Floats
复制标题
卫星测高和 Argo 浮标重建厄加勒斯环温盐结构的演化
DOI：
10.1029/2018jc014426
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发表时间：
2019
影响因子：
--
通讯作者：
A. Stegner
中科院分区：
文献类型：
--
作者：
R. Laxenaire;S. Speich;A. Stegner
印度洋温跃层和中层沃茨通过厄古拉斯泄漏进入南大西洋，一般认为主要是通过中尺度涡流过程完成的，基本上是称为厄古拉斯环的反气旋。在这里，我们利用最近的涡流跟踪算法和Argo浮标剖面研究这些涡流之一的演变和温盐结构在1.5年的过程中（2013年5月至2014年11月）。我们发现，在此期间，环演变根据两个不同的阶段：在第一个，发生在冬季，在涡的混合层显着加深。在第二阶段，涡下沉到南大西洋副热带环流的上层温暖层以下，同时向西传播。这种涡流从海面分离可以解释卫星测高图中其表面特征的减少，这表明这种变化不是由于涡流耗散过程。它是一个非常大的涡流（体积为7.1×1013 m3），在俯冲后从200- 1，200 m深度延伸，其特征是具有两种模式的水核。与周围相比，两种模式的水芯代表最大的涡动热盐异常。就其一年的影响而言，这一长寿反气旋向西北方向的传播导致了2.2 Sv的水、0.008 PW的热量和2.2×105 kg s−1的盐的输送。这些结果证实了厄古拉斯环在印度洋-大西洋海洋间的热盐交换中起着非常重要的作用。印度洋沃茨向南大西洋的转移通常被认为主要是通过被称为阿古拉斯环的反气旋涡旋完成的。有各种各样的研究调查这些涡从稀疏的现场和卫星观测。在这里，我们利用从卫星地图和测量海洋上部2 000米的自由漂移剖面浮标检测到的漩涡提供的补充信息，重建其中一个海洋的内部结构。这张重建图显示，这条阿古拉斯环离开了表层，并在向西漂移进入大西洋的过程中慢慢沉入地下。环是一个非常大的漩涡，延伸到1,200米深，其特点是两个核心显示温度异常高达4摄氏度时，与周围的南大西洋沃茨。这些结果证实了厄古拉斯环在印度洋-大西洋海洋间的热盐交换中起着非常重要的作用。
The transfer of Indian Ocean thermocline and intermediate waters into the South Atlantic via the Agulhas leakage is generally believed to be primarily accomplished through mesoscale eddy processes, essentially anticyclones known as Agulhas Rings. Here we take advantage of a recent eddy tracking algorithm and Argo float profiles to study the evolution and the thermohaline structure of one of these eddies over the course of 1.5 years (May 2013–November 2014). We found that during this period the ring evolved according to two different phases: During the first one, taking place in winter, the mixing layer in the eddy deepened significantly. During the second phase, the eddy subsided below the upper warmer layer of the South Atlantic subtropical gyre while propagating west. The separation of this eddy from the sea surface could explain the decrease in its surface signature in satellite altimetry maps, suggesting that such changes are not due to eddy dissipation processes. It is a very large eddy (7.1×1013 m3 in volume), extending, after subduction, from a depth of 200–1,200 m and characterized by two mode water cores. The two mode water cores represent the largest eddy heat and salt anomalies when compared with the surrounding. In terms of its impact over 1 year, the north-westward propagation of this long-lived anticyclone induces a transport of 2.2 Sv of water, 0.008 PW of heat, and 2.2×105 kg s−1 of salt. These results confirm that Agulhas Rings play a very important role in the Indo-Atlantic interocean exchange of heat and salt. Plain Language Summary The transfer of the Indian Ocean waters to the South Atlantic Ocean is generally believed to be primarily accomplished through anticyclonic eddies known as Agulhas Rings. There have been various studies investigating these eddies from sparse in situ and satellite observations. Here we take the advantage of the complementary information provided by eddies detected from satellite maps and free-drifting profiling floats measuring the upper 2,000 m of the ocean, to reconstruct the internal structure of one of them. This reconstruction shows that this Agulhas Ring quits the surface layer and slowly sinks into the subsurface as it drifts westward into the Atlantic Ocean. The ring is a very large eddy extending down to 1,200 m of depth and characterized by two cores showing temperature anomalies up to 4 ◦C when compared with the surrounding South Atlantic waters. These results confirm that Agulhas Rings play a very important role in the Indo-Atlantic interocean exchange of heat and salt.
影响因子：
64.8
作者：
Biastoch, A.;Boening, C. W.;Lutjeharms, J. R. E.
通讯作者：
Lutjeharms, J. R. E.
影响因子：
64.8
作者：
Biastoch, A.;Boening, C. W.;Lutjeharms, J. R. E.
通讯作者：
Lutjeharms, J. R. E.