Antarctic ice shelf disintegration triggered by sea ice loss and ocean swell

The data are from our Nature Article from June 2018: "Antarctic ice shelf disintegration triggered by sea ice loss and ocean swell".

The abstract is:
"Understanding the causes of recent catastrophic ice shelf disintegrations is a crucial step towards improving coupled models of the Antarctic Ice Sheet and predicting its future state and contribution to sea-level rise. An overlooked climate-related causal factor is regional sea ice loss. Here we show that for the disintegration events observed (the collapse of the Larsen A and B and Wilkins ice shelves), the increased seasonal absence of a protective sea ice buffer enabled increased flexure of vulnerable outer ice shelf margins by ocean swells that probably weakened them to the point of calving. This outer-margin calving triggered wider-scale disintegration of ice shelves compromised by multiple factors in preceding years, with key prerequisites being extensive flooding and outer-margin fracturing. Wave-induced flexure is particularly effective in outermost ice shelf regions thinned by bottom crevassing. Our analysis of satellite and ocean-wave data and modelling of combined ice shelf, sea ice and wave properties highlights the need for ice sheet models to account for sea ice and ocean waves."

Details of the analyses and data used, and the data generated by this study, are given in the paper: https://www.nature.com/articles/s41586-018-0212-1.

Code availability: Analytical scripts used in this study are freely available from the authors
via the corresponding author upon reasonable request.

Data availability: The datasets and products generated during the current study are available from the corresponding author on reasonable request.

The datasets forming the basis of the study are available as follows:

(1) Sea ice: Daily estimates of satellite-derived sea ice concentration (gridded at a spatial
resolution of 25 x 25 km) derived by the NASA Bootstrap algorithm for the period 1979-2010 were obtained from the US National Snow and Ice Data Center (NSIDC) dataset at:
http://nsidc.org/data/NSIDC-0079. Accessed August 2015.

(2) Waves: Ocean wave-field data were obtained from the CAWCR (Collaboration for
Australian Weather and Climate Research) Wave Hindcast 1979–2010 dataset run on a 0.4 x 0.4° global grid: https://doi.org/10.4225/08/523168703DCC5. Accessed September 2017.

(3) Satellite visible and thermal infrared imagery of ice shelves and disintegration events: The NOAA AVHRR image of the Larsen1995 disintegration used in Figure 2 was obtained from the British Antarctic Survey: http://www.nerc-bas.ac.uk/icd/bas_publ.html. Accessed June 2015.
MODIS visible and 839 thermal infrared imagery from the US NSIDC archive at:
http://nsidc.org/data/iceshelves_images/. Accessed June 2012.

The study involved 2 model components, and model output is described below. The 2 models are: (i) a model of ocean swell attenuation by sea ice; and (ii) an ice shelf-ocean wave interaction model. Descriptions of both are given in the Nature paper (Methods section).

DESCRIPTIONS OF THE 13 INDIVIDUAL DATA FILES PROVIDED (NB DESCRIPTIONS OF DATASETS GENERATED RELATIVE TO THE FIGURES) ARE GIVEN IN THE FILES:
(1) Source data for Figures 4 (parts a-d), 5 and 6a are given in Excel spreadsheet files "Source-Data_2017-07-09041A_Figure.....xlsx".

(2) Source data for Extended Data Figures 1 (parts a-b), 3 (parts b,d and parts a,c), 4 (parts b,d and a,c) and 6 are given in Excel spreadsheet files "Source-Data_2017-07-09041A_EDFig.....xlsx".

本数据集源自2018年6月发表于《自然》（Nature）的论文《海冰消退与海浪引发的南极冰架（ice shelf）崩解》。

论文摘要如下：解析近期灾难性冰架崩解事件的成因，是优化南极冰盖（Antarctic Ice Sheet）耦合模型、预测其未来状态及对海平面上升（sea-level rise）贡献的关键环节。此前被忽视的一类与气候相关的成因要素为区域海冰（sea ice）消退。本文针对观测到的拉森A、拉森B与威尔金斯冰架崩解事件，证实：季节性保护性海冰缓冲层缺失范围的扩大，使得海浪对脆弱冰架外缘的弯曲形变作用增强，进而将冰架弱化至发生冰崩（calving）的临界状态。此类外缘冰崩触发了此前多年受多种因素影响而弱化的冰架发生更大范围的崩解，其关键前提为大面积融水泛滥与外缘断裂。海浪诱导的弯曲形变对因底部裂隙发生变薄的冰架外缘区域尤为显著。本研究通过卫星与海浪数据分析，以及冰架、海冰与海浪属性的联合建模，强调了冰盖模型需纳入海冰与海浪因子的必要性。

本研究的分析细节、所用数据及生成数据集的具体信息详见该论文：https://www.nature.com/articles/s41586-018-0212-1。

代码可用性：本研究所用的分析脚本可应合理请求，向通讯作者获取。

数据可用性：本研究生成的数据集与相关成果，可应合理请求向通讯作者获取。

构成本研究基础的数据集获取方式如下：
(1) 海冰数据：1979-2010年的卫星反演海冰浓度日估算值（空间分辨率为25×25 km）由NASA Bootstrap算法（NASA Bootstrap algorithm）生成，获取自美国国家冰雪数据中心（US National Snow and Ice Data Center, NSIDC）数据集，链接为http://nsidc.org/data/NSIDC-0079，获取时间为2015年8月。
(2) 海浪数据：1979-2010年全球0.4×0.4°网格的海浪场回溯数据集（Wave Hindcast），由澳大利亚天气与气候研究合作中心（Collaboration for Australian Weather and Climate Research, CAWCR）生成，链接为https://doi.org/10.4225/08/523168703DCC5，获取时间为2017年9月。
(3) 冰架及崩解事件的卫星可见光与热红外影像：用于图2的拉森1995年崩解事件NOAA AVHRR影像获取自英国南极调查局（British Antarctic Survey），链接为http://www.nerc-bas.ac.uk/icd/bas_publ.html，获取时间为2015年6月。MODIS可见光与839热红外影像存档于美国国家冰雪数据中心（NSIDC），链接为http://nsidc.org/data/iceshelves_images/，获取时间为2012年6月。

本研究包含两类模型组件，模型输出说明如下。两类模型分别为：(i) 海冰对海浪的衰减模型（ocean swell attenuation by sea ice）；(ii) 冰架-海浪相互作用模型（ice shelf-ocean wave interaction model）。两类模型的详细说明均见上述《自然》论文的方法部分（Methods section）。

本次提供的13个独立数据文件说明（注：生成数据集与对应图件的关联说明详见各文件）如下：
(1) 图4（a-d分图）、图5及图6a的源数据存储于Excel电子表格文件"Source-Data_2017-07-09041A_Figure.....xlsx"。
(2) 扩展数据图1（a-b分图）、扩展数据图3（b、d及a、c分图）、扩展数据图4（b、d及a、c分图）及扩展数据图6的源数据存储于Excel电子表格文件"Source-Data_2017-07-09041A_EDFig.....xlsx"。