Spatial and temporal variability of 21st century sea level changes
Spatial and temporal variability of 21st century sea level changes
复制标题
21世纪海平面变化的时空变化
DOI：
10.1093/gji/ggad170
复制
发表时间：
2023
影响因子：
2.8
通讯作者：
Nowicki, Sophie
中科院分区：
文献类型：
--
作者：
Roffman, Jeremy;Gomez, Natalya;Yousefi, Maryam;Han, Holly Kyeore;Nowicki, Sophie
极地冰盖的质量损失正在成为当前海平面变化的主要因素，也是海平面预测中最大的不确定性来源之一。海平面变化的空间格局对冰盖质量变化的几何形状非常敏感，由于重力、地球自转和变形（GRD）效应，局部海平面变化可能偏离全球平均海平面变化。与冰盖融化相关的GRD海平面变化模式通常被认为在冰盖附近以外的时间上保持相对恒定。例如，在最近的IPCC第六次评估报告（AR6）的海平面预测中，冰盖质量损失的几何形状被视为在21世纪中保持不变。然而，冰盖模拟预测，在未来世纪，给定冰盖上冰质量变化的几何形状以及每个冰盖的相对质量损失将有所不同，从而产生时空可变的全球海平面变化模式。我们采用一个海平面模型，包括GRD效应和海岸线迁移计算随时间变化的海平面模式与格陵兰岛和南极冰盖的预测在未来世纪。我们发现，在某些情况下，海平面变化可以大大放大以上的全球平均水平在世纪初，这种放大缩小到2100年。我们解释了这些差异，分别计算地球自转的贡献，以及重力和变形的影响，预计海平面的变化。我们发现，在一种情况下，例如，南极半岛的冰增益可以导致放大高达2.9倍的全球平均海平面当量沿着南美海岸线由于积极的干扰GRD的影响。为了探讨预测的冰质量几何形状的差异所带来的不确定性，我们预测海平面变化后的端元质量损失的情况下，南极冰盖的各个地区从ISMIP6模式ensemblely，并发现海平面放大以上的全球平均海平面当量不同的冰质量预测沿着格陵兰岛和南极洲以外的全球海岸线之间的差异高达1.9倍。这项工作表明，未来的海平面危险的评估，不仅要考虑综合质量变化的冰盖，但也在整个冰盖的冰质量变化的几何形状的时间变化。此外，这项研究还强调了限制格陵兰和南极冰盖之间冰量变化相对时间的重要性。
Mass loss from polar ice sheets is becoming the dominant contributor to current sea level changes, as well as one of the largest sources of uncertainty in sea level projections. The spatial pattern of sea level change is sensitive to the geometry of ice sheet mass changes, and local sea level changes can deviate from the global mean sea level change due to gravitational, Earth rotational and deformational (GRD) effects. The pattern of GRD sea level change associated with the melting of an ice sheet is often considered to remain relatively constant in time outside the vicinity of the ice sheet. For example, in the sea level projections from the most recent IPCC sixth assessment report (AR6), the geometry of ice sheet mass loss was treated as constant during the 21st century. However, ice sheet simulations predict that the geometry of ice mass changes across a given ice sheet and the relative mass loss from each ice sheet will vary during the coming century, producing patters of global sea level changes that are spatiotemporally variable. We adopt a sea level model that includes GRD effects and shoreline migration to calculate time-varying sea level patterns associated with projections of the Greenland and Antarctic Ice Sheets during the coming century. We find that in some cases, sea level changes can be substantially amplified above the global mean early in the century, with this amplification diminishing by 2100. We explain these differences by calculating the contributions of Earth rotation as well as gravitational and deformational effects to the projected sea level changes separately. We find in one case, for example, that ice gain on the Antarctic Peninsula can cause an amplification of up to 2.9 times the global mean sea level equivalent along South American coastlines due to positive interference of GRD effects. To explore the uncertainty introduced by differences in predicted ice mass geometry, we predict the sea level changes following end-member mass loss scenarios for various regions of the Antarctic Ice Sheet from the ISMIP6 model ensemblely, and find that sea level amplification above the global mean sea level equivalent differ by up to 1.9 times between different ice mass projections along global coastlines outside of Greenland and Antarctica. This work suggests that assessments of future sea level hazard should consider not only the integrated mass changes of ice sheets, but also temporal variations in the geometry of the ice mass changes across the ice sheets. As well, this study highlights the importance of constraining the relative timing of ice mass changes between the Greenland and Antarctic Ice Sheets.