Code and glacial isostatic adjustment model outputs associated with "Glacial isostatic adjustment driven by asymmetric ice sheet melt during the last interglacial causes multiple local sea level peaks"

### Access
NetCDF files be accessed and downloaded from the directory via: [http://arcticdata.io/data/10.18739/A2S756N0M](http://arcticdata.io/data/10.18739/A2S756N0M).

### Overview
This dataset comprises the code used to produce the results in Creel, R.C., Austermann, J.A., Glacial isostatic adjustment driven by asymmetric ice sheet melt during the Last Interglacial causes multiple local sea-level peaks. Geology. https://doi.org/10.1130/G52483.1.

Research abstract:

Global mean sea-level (GMSL) change during the Last Interglacial (LIG, 129−116 kiloannum (ka)) gives perspective on how ice sheets respond to warming. Observations of multiple peaks in LIG relative sea level (RSL) records, combined with an assumption that the Laurentide Ice Sheet (LIS) collapsed prior to the LIG, have been used to infer Greenland and Antarctic ice sheet melt histories as well as oscillations in LIG GMSL. However, evidence for an LIS outburst flood at ca. 125 ka and extensive early-LIG Antarctic melt suggests that Laurentide remnants may have persisted longer into the LIG than typically thought even as Antarctic melt accelerated. Here, we explore the effect of concurrent early-Holocene Laurentide persistence and Antarctic collapse on glacial isostatic adjustment and sea level. In our models, we hold GMSL constant at present levels (i.e., GMSL = 0) from 128 ka to 117 ka by balancing excess Laurentide ice with early-LIG Antarctic melt. We find that due to glacial isostatic adjustment, this synchronous but asymmetric ice change causes multiple RSL peaks, separated by ∼4.2 ± 2.5 m of RSL fall near North America and ∼1.3 ± 0.7 m around the Indian Ocean. This spatial pattern resembles observations. These results show that multiple peaks in LIG RSL could have occurred with asymmetric ice changes between the Northern and Southern Hemisphere that sum to little, if any, change in GMSL. Our work highlights the need for LIG modeling studies to consider that dynamic cryospheric changes can occur even with near-constant GMSL.

This research was conducted at Lamont Doherty Earth Observatory in 2022 and 2023. It is entirely composed of modeling and compilation of existing data; no new data were produced for the study. The methodologies employed include glacial isostatic adjustment modeling using MATLAB code written by Jacky Austermann and post-processing of the resulting models using python scripts written by Roger Creel.

### 访问方式
可通过以下链接从对应目录获取并下载网络通用数据格式（NetCDF）文件：[http://arcticdata.io/data/10.18739/A2S756N0M](http://arcticdata.io/data/10.18739/A2S756N0M)

### 数据集概况
本数据集包含用于复现Creel RC、Austermann JA发表于《Geology》的论文《末次间冰期不对称冰盖消融驱动的冰川均衡调整引发多区域海平面峰》（https://doi.org/10.1130/G52483.1）中各项结果的代码。

**研究摘要**
末次间冰期（Last Interglacial, LIG，129~116千年前，kiloannum, ka）的全球平均海平面（Global Mean Sea-Level, GMSL）变化，为理解冰盖对气候变暖的响应机制提供了重要参考。针对末次间冰期相对海平面（Relative Sea Level, RSL）记录中多峰特征的观测结果，结合劳伦泰德冰盖（Laurentide Ice Sheet, LIS）在末次间冰期前已完全消融的假设，学界曾用以推断格陵兰与南极冰盖的消融历史，以及末次间冰期全球平均海平面的振荡情况。然而，约12.5万年前劳伦泰德冰盖溃决洪水的相关证据，以及末次间冰期早期南极冰盖大规模消融的现象表明：尽管南极冰盖消融速率加快，劳伦泰德冰盖的残余部分可能比学界普遍认知的更晚才在末次间冰期完全消融。

本研究探讨了全新世早期劳伦泰德冰盖残余留存与南极冰盖消融同步发生时，对冰川均衡调整及海平面变化的影响。在模型构建中，我们通过平衡过剩的劳伦泰德冰量与末次间冰期早期南极冰盖消融量，将12.8万年前至11.7万年前的全球平均海平面维持在现代水平（即全球平均海平面变化量为0）。研究结果显示，受冰川均衡调整的影响，这种同步但不对称的冰量变化会引发多阶段相对海平面峰：北美附近区域相对海平面下降幅度约为4.2±2.5米，印度洋周边区域则约为1.3±0.7米。该空间分布特征与实际观测结果相符。

本研究结果表明，即便南北半球冰量变化不对称，但两者对全球平均海平面的总影响近乎为零的情况下，末次间冰期相对海平面仍可能出现多峰特征。本研究强调，在末次间冰期相关模拟研究中，即便全球平均海平面近乎恒定，也应考虑到冰冻圈的动态变化过程。

本研究于2022至2023年在拉蒙特-多尔蒂地球观测站（Lamont Doherty Earth Observatory）开展，所有内容均基于现有数据的建模与汇编，未产生全新的观测数据。研究所采用的方法包括：由Jacky Austermann编写的MATLAB代码开展冰川均衡调整模拟，以及由Roger Creel编写的Python脚本对模拟结果进行后处理。