Universidade de São Paulo, Departamento de Engenharia Mecânica, Escola Politécnica, Av. Prof. Mello Moraes 2231, 05508-030 São Paulo, SP, Brazil.
Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS, Brazil.
An Acad Bras Cienc. 2023 Oct 9;95(suppl 3):e20210560. doi: 10.1590/0001-3765202320210560. eCollection 2023.
The Lange glacier is an outlet glacier situated in the Admiralty Bay, King George Island, Peninsula Antarctica. It retreated about 1 km since the 1950s. Although recent observations do not show any significant change at the ice-ocean margin, it is not clear whether this glacier has reached a new steady state or whether it is still adjusting to new climate conditions. By combining a three-dimensional glacier model with satellite and in-situ datasets, we investigate the sensitivity of Lange glacier to perturbations in flow rate factor, friction coefficient, surface mass balance, and calving front position. The (time-dependent) perturbation experiments show that the glacier is more sensitive to changes in surface mass balance and in flow rate factor. These results suggest that the climate variability of this region plays an important role on the glacier's dynamics, and that measurements of englacial temperature will improve the reliability of future modeling efforts. Our model shows that the position of the ice front exerts a strong control on the glacier flux. In our time-dependent simulation, the impacts of the observed front retreat on the glacier's dynamics persist beyond the present date. This suggests that Lange is likely still adjusting to past perturbations at its terminus.
朗格冰川是位于南极洲乔治王岛阿德默勒尔蒂湾的一条外流冰川。自 20 世纪 50 年代以来，它已经后退了约 1 公里。尽管最近的观测结果表明在冰海边缘没有任何显著变化，但尚不清楚这条冰川是否已经达到新的稳定状态，还是仍在适应新的气候条件。我们通过将一个三维冰川模型与卫星和现场数据集相结合，研究了朗格冰川对流速因子、摩擦系数、表面质量平衡和崩解前沿位置的扰动的敏感性。（时变）扰动实验表明，冰川对表面质量平衡和流速因子的变化更为敏感。这些结果表明，该地区的气候变率对冰川动力学起着重要作用，而冰内温度的测量将提高未来建模工作的可靠性。我们的模型表明，冰前位置对冰川流量有很强的控制作用。在我们的时变模拟中，观测到的前缘后退对冰川动力学的影响一直持续到现在以后的日期。这表明，朗格冰川可能仍在调整其末端的过去扰动。
