Understanding ice shelf–ocean interaction is fundamental to projecting the Antarctic ice sheet response to a warming climate. Numerical ice shelf–ocean models are a powerful tool for simulating this interaction, yet are limited by inherent model weaknesses and scarce observations, leading to parameterisations that are unverified and unvalidated below ice shelves. We explore how different models simulate ice shelf–ocean interaction using the 2nd Ice Shelf–Ocean Model Intercomparison Project (ISOMIP+) framework. Vertical discretisation and resolution of the ocean model are shown to have a significant effect on ice shelf basal melt rate, through differences in the distribution of meltwater fluxes and the calculation of thermal driving. Z-coordinate models, which generally have coarser vertical resolution in ice shelf cavities, may simulate higher melt rates compared to terrain-following coordinate models. This is due to the typically higher resolution of the ice–ocean boundary layer region in terrain following models, which allows better representation of a thin meltwater layer, increased stratification, and as a result, better insulation of the ice from water below. We show that a terrain-following model, a z-level coordinate model and a hybrid approach give similar results when the effective vertical resolution adjacent to the ice shelf base is similar, despite each model employing different paradigms for distributing meltwater fluxes and sampling tracers for melting. We provide a benchmark for thermodynamic ice shelf–ocean interaction with different model vertical coordinates and vertical resolutions, and suggest a framework for any future ice shelf–ocean thermodynamic parameterisations.

中文翻译：

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垂直过程和分辨率影响冰架基底融化：多模型研究

了解冰架-海洋相互作用对于预测南极冰盖对气候变暖的反应至关重要。数值冰架 - 海洋模型是模拟这种相互作用的强大工具，但受到固有模型弱点和稀缺观察的限制，导致冰架下未经验证和未经验证的参数化。我们探索不同模型如何使用第二个冰架-海洋模型比对项目 (ISOMIP+) 框架模拟冰架-海洋相互作用。通过融水通量分布的差异和热驱动的计算，表明海洋模型的垂直离散化和分辨率对冰架基础融化速率有显着影响。Z 坐标模型，通常在冰架空腔中具有较粗的垂直分辨率，与地形跟随坐标模型相比，可以模拟更高的熔化速率。这是由于地形跟随模型中冰海边界层区域的分辨率通常更高，这可以更好地表示薄的融水层，增加分层，从而更好地将冰与水隔离。我们表明，当与冰架底部相邻的有效垂直分辨率相似时，地形跟随模型、z 级坐标模型和混合方法给出了相似的结果，尽管每个模型采用不同的范式来分配融水通量和采样示踪剂融化。我们为具有不同模型垂直坐标和垂直分辨率的热力学冰架-海洋相互作用提供了基准，