近日，美国达特茅斯学院Jessica A. Badgeley团队研究了格陵兰西北部对重现观测的模式海平面贡献的增加。相关论文于2025年6月16日发表在《美国科学院院刊》杂志上。

为政府间气候变化专门委员会提供信息的冰盖模型比对项目（ISMIP）中使用的最先进的冰盖模型模拟往往低估了格陵兰冰盖观测到的质量损失，从而引发了未来海平面上升是否可能大于预测的问题。研究组使用其中一个模型，即冰盖和海平面系统模型，来研究瞬态校准如何影响历史和投影模拟。瞬态校准是冰流模型中一种新兴的能力；它使用表面观测的时间序列和时变物理来约束不确定的模型参数——在这种情况下，是滑动定律中的基础摩擦系数。由于比常见的快照反演方法有更多的约束，瞬态校准已被证明可以更好地捕捉冰动力学的趋势。 

研究组将这两种方法应用于格陵兰岛西北部，一个正在经历快速变化的地区。对于用快照反演初始化的模拟，他们发现后续的建模速度通常太慢，导致对质量损失的低估。然而，通过瞬态校准，该模拟更好地匹配了观测到的速度的时间序列，使其在质量损失的观测误差范围内；然而，与观测到的表面高程的拟合度略有降低。结合ISMIP的结果，该模拟表明，再现历史上的高质量损失率会导致该地区在未来一个世纪对海平面的贡献更大。最后，该研究提出了一条前进的道路，使瞬态校准可扩展到整个格陵兰冰盖。

附：英文原文

Title: Increased sea-level contribution from northwestern Greenland for models that reproduce observations

Author: Badgeley, Jessica A., Morlighem, Mathieu, Seroussi, Hélène

Issue&Volume: 2025-6-16

Abstract: State-of-the-art ice sheet model simulations used in the Ice Sheet Model Intercomparison Project (ISMIP) that informs the Intergovernmental Panel on Climate Change tend to underestimate observed mass loss from the Greenland Ice Sheet, leading to the question of whether future sea-level rise may be larger than projected. We use one of these models, the Ice-sheet and Sea-level System Model, to investigate how transient calibration impacts historical and projection simulations. Transient calibration is an emerging capability in ice flow models; it uses time series of surface observations and time-dependent physics to constrain uncertain model parameters—in this case, the basal friction coefficient in the sliding law. With more constraints than the common snapshot inversion method, transient calibration has been shown to better capture trends in ice dynamics. Here, we apply both methods to northwestern Greenland, a region undergoing rapid changes. For simulations initialized with the snapshot inversion, we find that subsequent modeled velocities are generally too slow, leading to an underestimation of the mass loss. With transient calibration, however, our simulation better matches a time series of observed velocities, bringing it within observational error for mass loss; however, the fit to observed surface elevation is slightly reduced. Together with the ISMIP results, our simulations show that reproducing the high rates of historical mass loss leads to greater projected sea-level contribution from this region over the coming century. Finally, we suggest a path forward for making transient calibration scalable to the entire Greenland Ice Sheet.

DOI: 10.1073/pnas.2411904122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2411904122