Some Implications of Ekman Layer Dynamics for Cross-Shelf Exchange in the Amundsen Sea
Some Implications of Ekman Layer Dynamics for Cross-Shelf Exchange in the Amundsen Sea
复制标题
艾克曼层动力学对阿蒙森海跨陆架交换的一些影响
DOI：
10.1175/jpo-d-11-041.1
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发表时间：
2012
影响因子：
3.5
通讯作者：
H. Alsén
中科院分区：
文献类型：
--
作者：
A. Wåhlin;R. Muench;L. Arneborg;G. Björk;H. K. Ha;Sang H. Lee;H. Alsén
温暖的、含盐的海水穿过南极西部大陆架的交换导致海洋和南极西部冰原交界面的地下冰川融化。造成跨陆架运输的一种机制是由沿坡流在坡上和陆架断裂引起的ekman运输。对这一过程的调查应用于阿蒙森海大陆架断裂区域，使用最近获得的历史现场数据来指导分析。沿坡流在阿蒙森坡的东部和西部的横断面上被观测到。东边的水流向东流，西边的水流向西流。在向东流动的海流下，水文等值线向上倾斜，与海底平行。在这一层中，下降的浮力而不是摩擦力使海底的速度为零。陆架东部的盆地水主要来自800 - 1000米深度的陆架水，这表明这种水在陆架上的输送经常发生。作者认为，受阻的Ekman层机制可以为东部陆架断裂提供深水，使其能够进入陆架。由于在西部陆架上没有发现未改性的离架水，底层Ekman输送不可能是向西部陆架地区输送温暖深水的机制。暖底水的变暖在西部大陆架最为明显，在过去十年中，那里的深水温度上升了0.68℃。
Theexchangeofwarm,saltyseawateracrossthecontinentalshelvesoffWestAntarcticaleadstosubsurface glacial melting at the interface between the ocean and the West Antarctic Ice Sheet. One mechanism that contributesto the cross-shelf transportis Ekmantransportinduced by along-slope currentsoverthe slope and shelf break. An investigation of this process is applied to the Amundsen Sea shelfbreak region, using recently acquiredandhistoricalfielddatatoguidetheanalyses.Along-slopecurrentswereobservedattransectsacross the eastern and western reaches of the Amundsen slope. Currents in the east flowed eastward, and currents farther west flowed westward. Under the eastward-flowing currents, hydrographic isolines sloped upward paralleling the seabed. In this layer, declining buoyancy forces rather than friction were bringing the velocity to zero at the seabed.Thebasin water in the easternpart ofthe shelfwas dominatedby wateroriginating from 800‐1000-m depth off shelf, suggesting that transport of such water across the shelf frequently occurs. The authors show that arrested Ekman layers mechanism can supply deep water to the shelf break in the eastern section, where it has access to the shelf. Because no unmodified off-shelf water was found on the shelf in the western part, bottom layer Ekman transport does not appear a likely mechanism for delivery of warm deep water to the western shelf area. Warming of the warm bottom water was most pronounced on the western shelf, where the deep-water temperature increased by 0.68C during the past decade.