An ensemble of Antarctic deglacial simulations constrained by geological observations
An ensemble of Antarctic deglacial simulations constrained by geological observations
复制标题
受地质观测限制的南极冰消模拟集合
DOI：
10.1016/j.quascirev.2022.107800
复制
发表时间：
2022
影响因子：
4
通讯作者：
Pittard M
中科院分区：
文献类型：
--
作者：
Pittard M
南极冰盖有可能对未来海平面上升做出重大贡献。了解这种潜力并预测未来冰盖的质量变化需要使用数值模型。模型预测的可信度可以通过后报来提高：根据过去的冰盖变化测试模型。强大的冰消模型重建也被用来纠正卫星重力测量冰川均衡调整过程中的电流变化。在这里，我们提出了一个新的模型合奏后末次冰期最大南极冰消重建。合奏是使用平行冰盖模型（PISM），其中我们改变了一系列参数，包括关键的冰川控制，基底沉积物强度，地幔粘度和气候强迫。我们测试的合奏结果对数据库的地质约束，并制定了一个新的评分方案，使我们能够确定对过去的冰盖接地线范围，冰盖厚度和变薄率，以及现今的冰盖配置模型性能的指标。我们讨论的参数组合，导致得分最高的模拟，我们也比较我们的合奏性能与现有的出版的冰川消退模型，使用相同的评分方案。探索得分最高的合奏成员的特点突出了一些关键功能的冰川消退的行为，包括一个相对狭窄的范围内的过去多余的冰量在末次冰期，全新世撤退后，今天的接地线与相称的体积最小值，和readvance行为。比较还使我们能够确定更多的地质数据将具有高约束力的冰盖模型的地区。
The Antarctic ice sheet has the potential to make a significant contribution to future sea-level rise. Understanding this potential and making projections of future ice sheet mass change requires use of numerical models. Confidence in model projections can be improved by hindcasting: testing the model against past ice sheet changes. Robust deglacial model reconstructions are also used to correct satellite gravimetric measurements of current change for glacial isostatic adjustment processes. Here we present a new model ensemble of post-Last Glacial Maximum Antarctic deglaciation reconstructions. The ensemble is generated using the Parallel Ice Sheet Model (PISM) in which we vary a range of parameters including key glaciological controls, basal sediment strength, mantle viscosity, and climate forcing. We test the ensemble results against a database of geological constraints, and develop a new scoring scheme that allows us to determine metrics of model performance against past ice sheet grounding line extent, ice sheet thickness, and thinning rates, as well as present-day ice sheet configuration. We discuss the parameter combinations that lead to the highest-scoring simulations and we also compare our ensemble performance with existing published deglacial models, using the same scoring scheme. Exploring the characteristics of the highest-scoring ensemble members highlights some key features of deglacial behaviour including a relatively narrow range of past excess ice volumes at the LGM, Holocene retreat behind present-day grounding lines with commensurate volume minima, and readvance behaviours. The comparison also allows us to identify areas where more geological data would have high constraining power for ice sheet models.