Bathymetric influences on Antarctic ice-shelf melt rates
Bathymetric influences on Antarctic ice-shelf melt rates
复制标题
水深测量对南极冰架融化速率的影响
DOI：
10.1002/essoar.10503016.1
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Goldberg D
中科院分区：
文献类型：
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作者：
Goldberg D
海洋测深对南极冰架空腔内的冰盖-海洋相互作用施加了强有力的控制，在那里它可以限制温暖、稠密的水进入漂浮冰架的底部。然而，海洋测深在冰架内或冰架附近测量是具有挑战性的。目前尚不清楚现有测深数据集的不确定性如何影响模拟的亚冰架融化速率。在这里，我们通过海洋环流模式的伴随物，用网格尺度的细节推断冰架融化速率对水深形状的线性敏感性。南极西部亚冰架空洞的理想和现实几何实验都表明，水深测量对局部区域的融化有很强的影响，例如地形障碍对流动的影响。此外，熔体对水深扰动的响应是非单调的，随着深度的加深，熔体的增加或减少取决于位置。我们的计算方法提供了一种全面的识别区域的方法，在这些区域中，精确的测深知识最具影响力，而且测深误差对模拟的冰盖-海洋相互作用的影响相对较小。
Ocean bathymetry exerts a strong control on ice sheet‐ocean interactions within Antarctic ice‐shelf cavities, where it can limit the access of warm, dense water at depth to the underside of floating ice shelves. However, ocean bathymetry is challenging to measure within or close to ice‐shelf cavities. It remains unclear how uncertainty in existing bathymetry datasets affect simulated sub‐ice‐shelf melt rates. Here we infer linear sensitivities of ice‐shelf melt rates to bathymetric shape with grid‐scale detail by means of the adjoint of an ocean general circulation model. Both idealized and realistic‐geometry experiments of sub‐ice‐shelf cavities in West Antarctica reveal that bathymetry has a strong impact on melt in localized regions such as topographic obstacles to flow. Moreover, response of melt to bathymetric perturbation is found to be non‐monotonic, with deepening leading to either increased or decreased melt depending on location. Our computational approach provides a comprehensive way of identifying regions, where refined knowledge of bathymetry is most impactful, and also where bathymetric errors have relatively little effect on modeled ice sheet‐ocean interactions.