Surface Melt and Runoff on Antarctic Ice Shelves at 1.5°C, 2°C, and 4°C of Future Warming
Surface Melt and Runoff on Antarctic Ice Shelves at 1.5°C, 2°C, and 4°C of Future Warming
复制标题
DOI：
10.1029/2020gl091733
复制
发表时间：
2021-04-28
影响因子：
5.2
通讯作者：
Kittel, C.
中科院分区：
文献类型：
--
作者：
Gilbert, E.;Kittel, C.
南极冰架未来的表面质量平衡（SMB）还没有得到足够分辨率和复杂性的模型的约束。在此，我们利用高分辨率的区域大气模式和来自四个CMIP模式的未来模拟来评估比工业化前温度升高1.5℃、2℃和4℃对SMB的可能影响。我们发现熔体和径流的非线性增长导致SMB在变暖更明显的情况下变得不那么积极。因此，南极冰架可能更有可能通过水力压裂引起的崩塌间接促进海平面上升，从而加速冰川的排放。利用径流和融水作为冰架稳定性的指标，我们发现几个南极冰架（拉森冰架、威尔金斯冰架、松岛冰架和沙克尔顿冰架）在4摄氏度时很容易解体。与4摄氏度相比，将21世纪的变暖限制在2摄氏度将使易受水力压裂引起的崩塌影响的冰架面积减少一半。要了解未来南极冰架SMB需要复杂的计算机模型，而到目前为止，使用这些模型进行的研究很少。在此，我们使用高分辨率MAR模型探讨了在高于工业化前温度1.5℃、2℃和4℃的变暖情景下冰架SMB的变化。我们的研究结果表明，变暖导致SMB减少，因为高温会产生融水，融水随后会从冰架上流出，而且这种影响对变暖程度越高越明显。南极冰架可能会导致未来海平面上升，因为大量的融化和径流增加了它们对“水力压裂”的脆弱性，这是一种冰架破裂和解体的过程。限制未来的变暖将减少冰架的数量，这些冰架将容易通过这种机制崩溃。
The future surface mass balance (SMB) of Antarctic ice shelves has not been constrained with models of sufficient resolution and complexity. Here, we force the high-resolution Modele Atmospherique Regional with future simulations from four CMIP models to evaluate the likely effects on the SMB of warming of 1.5 degrees C, 2 degrees C, and 4 degrees C above pre-industrial temperatures. We find non-linear growth in melt and runoff which causes SMB to become less positive with more pronounced warming. Consequently, Antarctic ice shelves may be more likely to contribute indirectly to sea level rise via hydrofracturing-induced collapse, which facilitates accelerated glacial discharge. Using runoff and melt as indicators of ice shelf stability, we find that several Antarctic ice shelves (Larsen C, Wilkins, Pine Island, and Shackleton) are vulnerable to disintegration at 4 degrees C. Limiting 21st century warming to 2 degrees C will halve the ice shelf area susceptible to hydrofracturing-induced collapse compared to 4 degrees C.Plain Language Summary Whether Antarctic ice shelves are gaining or losing ice at the surface-their surface mass balance (SMB)-depends on many factors. To understand future Antarctic ice shelf SMB requires complex computer models, and until now, few studies using these models have been done. Here, we use the high-resolution MAR model to explore how ice shelf SMB changes under warming scenarios of 1.5 degrees C, 2 degrees C, and 4 degrees C above pre-industrial temperatures. Our results show that warming causes SMB to decrease because high temperatures produce meltwater, which then runs off the ice shelves, and that this effect is larger for greater levels of warming. Antarctic ice shelves may contribute to rising sea levels in future because larger amounts of melt and runoff increase their vulnerability to "hydrofracturing," a process whereby ice shelves crack and disintegrate. Limiting future warming will reduce the number of ice shelves that will be susceptible to collapse via this mechanism.