Modification by lateral mixing of the Warm Deep Water entering the Weddell Sea in the Maud Rise region
Modification by lateral mixing of the Warm Deep Water entering the Weddell Sea in the Maud Rise region
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通过横向混合进入莫德海隆地区威德尔海的温暖深水进行修改
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
B. Cisewski
中科院分区：
文献类型：
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作者：
H. Leach;V. Strass;B. Cisewski
源自北大西洋的深水被涡旋带过南极环极流，绕南极一周后，进入非洲南部的威德尔环流。当它这样做的时候，它从中深度上升到表面。独立的温度和盐度最大值，上和下环极深水，汇聚形成暖深水。这个位于威德尔环流东部南侧的水团的核心在拉扎列夫海向西流动时显示出特征的变化。在2005/2006年北极星巡航ANTXXIII/2期间，沿着60°和70°S之间的3°E、0°、3°W和6°W四个子午段进行了观测。这些结果表明，从莫德隆起（65°S, 3°W）的东部和北部及南部进入该地区的一系列非均匀的暖盐岩心逐渐融合，并向西变得更加均匀。等流上的势温方差逐渐减小，表明等流混合过程的存在。多元回归技术可以诊断涡旋扩散率，因此，等气旋和重气旋混合的相对重要性。结果表明，等流扩散系数在70 ~ 140 m2 s−1范围内，静流扩散系数约为3 × 10−6 m2 s−1。尺度分析表明，在暖深水岩心的侵蚀过程中，等泊扩散作用大于深泊扩散作用。
Deep water originating in the North Atlantic is transported across the Antarctic Circumpolar Current by eddies and, after circumnavigating of the Antarctic, enters the Weddell Gyre south of Africa. As it does so, it rises up from mid-depth towards the surface. The separate temperature and salinity maxima, the Upper and Lower Circumpolar Deep Waters, converge to form the Warm Deep Water. Cores of this water mass on the southern flank of the eastern Weddell Gyre show a change in characteristic as they flow westward in the Lazarev Sea. Observations have been made along four meridional sections at 3° E, 0°, 3° W and 6° W between 60 and 70° S during the Polarstern Cruise ANTXXIII/2 in 2005/2006. These show that a heterogeneous series of warm and salty cores entering the region from the east both north and south of Maud Rise (65° S, 3° W) gradually merge and become more homogeneous towards the west. The gradual reduction in the variance of potential temperature on isopycnals is indicative of isopycnic mixing processes. A multiple regression technique allows diagnosis of the eddy diffusivities and, thus, the relative importance of isopycnic and diapycnic mixing. The method shows that the isopycnic diffusivity lies in the range 70–140 m2 s−1 and the diapycnic diffusivity reaches about 3 × 10−6 m2 s−1. Scale analysis suggests that isopycnic diffusion dominates over diapycnic diffusion in the erosion of the Warm Deep Water cores.