The Influence of Pine Island Ice Shelf Calving on Basal Melting
The Influence of Pine Island Ice Shelf Calving on Basal Melting
复制标题
松岛冰架崩解对基底融化的影响
作者：
Bradley A
松岛冰架（PIIS）吃水深度与其下的海底脊的组合形成地形屏障，限制温暖的环极深水进入脊的近岸空腔，从而对PIIS基底消融施加重要控制。此外，PIIS最近经历了几次大的产犊事件，进一步的产犊可能会显着改变腔的几何形状。冰锋位置的变化，加上冰厚度的变化，可能会放松地形障碍，从而显着改变基础融化率。在这里，我们考虑过去的影响，和未来可能的，PIIS融化率的产犊事件。我们使用一个高分辨率的海洋模型来模拟融化速率在一个理想化的域，其几何形状捕捉松岛冰川的显着特征，和一个现实的几何形状准确地模拟它，探索如何影响融化速率。理想化的模拟结果表明，融化对产犊的反应对PIIS和海床洋脊之间的差距的厚度有敏感的依赖性，并告知我们对现实模拟的解释，这表明PIIS融化速率对最近的产犊没有显着的反应。然而，平均融化速率随着产犊的进一步增加而近似线性增加，并且一旦冰锋到达脊顶，相对于今天放大约10%，如果产犊保持其目前的速率，则需要不到十年的时间。这提供了强有力的证据，证明产犊可能是对南极西部冰盖的冰-海敏感性的重要贡献，但尚未探索。
The combination of the Pine Island Ice Shelf (PIIS) draft and a seabed ridge beneath it form a topographic barrier, restricting access of warm Circumpolar Deep Water to a cavity inshore of the ridge, thus exerting an important control on PIIS basal ablation. In addition, PIIS has recently experienced several large calving events and further calving could significantly alter the cavity geometry. Changes in the ice front location, together with changes in ice thickness, might relax the topographic barrier and thus significantly change basal melt rates. Here, we consider the impact of past, and possible future, calving events on PIIS melt rates. We use a high‐resolution ocean model to simulate melt rates in both an idealized domain whose geometry captures the salient features of Pine Island Glacier, and a realistic geometry accurately resembling it, to explore how calving affects melt rates. The idealized simulations reveal that the melt response to calving has a sensitive dependence on the thickness of the gap between PIIS and the seabed ridge and inform our interpretation of the realistic simulations, which suggest that PIIS melt rates did not respond significantly to recent calving. However, the mean melt rate increases approximately linearly with further calving, and is amplified by approximately 10% relative to present day once the ice front reaches the ridge‐crest, taking less than one decade if calving maintains its present rate. This provides strong evidence that calving may represent an important, but as yet unexplored, contribution to the ice‐ocean sensitivity of the West Antarctic Ice Sheet.