Modeling Ocean Eddies on Antarctica's Cold Water Continental Shelves and Their Effects on Ice Shelf Basal Melting
Modeling Ocean Eddies on Antarctica's Cold Water Continental Shelves and Their Effects on Ice Shelf Basal Melting
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DOI：
10.1029/2018jc014688
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发表时间：
2019-07
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影响因子：
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通讯作者：
S. Mack;M. Dinniman;J. Klinck;D. McGillicuddy;L. Padman
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文献类型：
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作者：
S. Mack;M. Dinniman;J. Klinck;D. McGillicuddy;L. Padman
海洋驱动的南极洲冰架基底融化速度的变化可以改变接地冰盖质量损失的速度并导致海平面变化。融化速率取决于海洋热量的流入，这是通过稳定的环流和涡流发生的。先前的研究已经证明了涡流对于受环极深水相对温暖的入侵影响的冰架的重要性。然而，冷水大陆架上的冰架主要由接地线附近的稠密的陆架水和冰架前部的轻质地表水融化。涡流对这些冰架基底融化的影响尚未被研究。我们研究罗斯海区域海洋模型何时何地解析涡流，并确定涡流过程对基底融化的影响。形成的漩涡的大小取决于水柱分层和纬度。我们使用水平网格分辨率为 5 公里和 1.5 公里的模拟，并在 1.5 公里模型中改变地形平滑程度。较高分辨率模型产生的涡流数量约为低分辨率模型的 2-2.5 倍。在所有模拟中，涡流在两个方向上穿过冰架前沿。然而，低分辨率模拟和高分辨率模拟之间的基础熔化没有显着变化。我们的结论是，需要更高分辨率的模型（<1公里）才能更好地表示罗斯海的涡流，但假设罗斯冰架的基底融化对我们完全解析涡流场的能力相对不敏感。
Changes in the rate of ocean-driven basal melting of Antarctica's ice shelves can alter the rate at which the grounded ice sheet loses mass and contributes to sea level change. Melt rates depend on the inflow of ocean heat, which occurs through steady circulation and eddy fluxes. Previous studies have demonstrated the importance of eddy fluxes for ice shelves affected by relatively warm intrusions of Circumpolar Deep Water. However, ice shelves on cold water continental shelves primarily melt from dense shelf water near the grounding line and from light surface water at the ice shelf front. Eddy effects on basal melt of these ice shelves have not been studied. We investigate where and when a regional ocean model of the Ross Sea resolves eddies and determine the effect of eddy processes on basal melt. The size of the eddies formed depends on water column stratification and latitude. We use simulations at horizontal grid resolutions of 5 and 1.5 km and, in the 1.5-km model, vary the degree of topography smoothing. The higher-resolution models generate about 2–2.5 times as many eddies as the low-resolution model. In all simulations, eddies cross the ice shelf front in both directions. However, there is no significant change in basal melt between lowand high-resolution simulations. We conclude that higher-resolution models (<1 km) are required to better represent eddies in the Ross Sea but hypothesize that basal melt of the Ross Ice Shelf is relatively insensitive to our ability to fully resolve the eddy field.