RAPID: What Caused the Record Warmth and Loss of Antarctic Sea ice in the Austral Summer of 2022, and will Sea Ice Remain Low Over 2022-2024?

RAPID：是什么导致 2022 年南半球夏季南极海冰出现创纪录的变暖和损失？2022-2024 年海冰是否会保持较低水平？

• 批准号: 2233016
• 负责人: Edward Blanchard-Wrigglesworth
• 金额: $ 8.42万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2233016&HistoricalAwards=false
• 关键词: RAPID; What; Caused; Record; Warmth

In the austral winter of 2021/2022 a drastic decline in Antarctic sea ice extent has taken place, and February 2022 marked the lowest sea ice extent on record since satellite sea ice observations began in 1979. Combined with the loss of sea ice, the most extreme heat wave ever observed took place over East Antarctica in March 2022 as temperatures climbed over +40°C from climatology. Extreme events have an oversized footprint in socioeconomic impacts, but also serve as litmus tests for climate predictions. This project will use novel tools to diagnose the factors that led to the record low Antarctic sea ice extent and heat wave focusing on the impact of winds and ocean temperatures. Currently (June 2022) Antarctic sea ice extent remains at record low levels for the time of year, raising the prospect of a long-lasting period of low sea ice extent, yet annual forecasts of Antarctic sea ice do not yet exist. To address this issue, this project will also create exploratory annual sea ice forecasts for the 2022-2024 period. The extreme changes observed in Antarctic sea ice extent and air temperature have questioned our current understanding of Antarctic climate variability. Motivated by the timing of these events and our recent development of novel analysis tools, this project will address the following research questions:(R1) Can local winds account for the observed 2021/2022 sea ice loss, or are remote sea surface temperature (SST) anomalies a necessary ingredient?(R2) Are sea ice conditions over 2022-2024 likely to remain anomalously low?(R3) Can a state-of-the-art climate model simulate a heat wave of comparable magnitude to that observed if it follows the observed circulation that led to the heat wave?The main approach will be to use a nudging technique with a climate model, in which one or several variables in a climate model are nudged toward observed values. The project authors used this tool to attribute Antarctic sea ice variability and trends over 1979-2018 to winds and SST anomalies. This project will apply this tool to the period 2019-2022 to address R1 and R3 by running two different model experiments over this time period in which the winds over Antarctica and SSTs in the Southern Ocean are nudged toward observed values. In addition, we will diagnose the relevant modes of atmospheric variability over 2019-2022 that are known to influence Antarctic sea ice to gain further insight into the 2022 loss of sea ice extent. To address R2, we plan to extend the model simulations but without nudging, using the model as a forecast model (as its 2022 initial conditions will be taken from the end of the nudged simulations and capture important aspects of the observed state). We expect that if current upper ocean heat content is anomalously high, low sea ice extent conditions may continue over 2022-2024, as happened over 2017-2019 following the previous record low of sea ice extent in 2016/2017. To further address R3, we will compare observations and model simulations using novel atmospheric heat transport calculations developed by the project team.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在2021/2022年的南极冬季，南极海冰范围急剧下降，2022年2月是自1979年开始卫星海冰观测以来有记录以来的最低海冰范围。再加上海冰的消失，有史以来最极端的热浪发生在2022年3月的南极洲东部，当时气候学上的温度超过了+40 ° C。极端事件对社会经济影响巨大，但也是气候预测的试金石。该项目将使用新的工具来诊断导致南极海冰范围创纪录低和热浪的因素，重点是风和海洋温度的影响。目前（2022年6月）南极海冰范围仍处于一年中的历史最低水平，这增加了长期低海冰范围的前景，但南极海冰的年度预测尚未存在。为了解决这一问题，该项目还将创建2022-2024年期间的探索性年度海冰预测。观察到的南极海冰范围和气温的极端变化质疑了我们目前对南极气候变异性的认识。受这些事件的时间和我们最近开发的新分析工具的启发，该项目将解决以下研究问题：（R1）当地风能否解释观测到的2021/2022年海冰损失，或者远程海面温度（SST）异常是必要的因素？(R2)2022-2024年的海冰状况是否可能保持低水平？(R3)如果一个最先进的气候模型遵循导致热浪的观测环流，那么它能模拟出与观测到的热浪相当的热浪吗？主要的方法将是在气候模式中使用一种推动技术，即气候模式中的一个或几个变量被推向观测值。项目作者使用该工具将1979-2018年南极海冰的变化和趋势归因于风和SST异常。该项目将在2019-2022年期间应用该工具，通过在这段时间内运行两个不同的模型实验来解决R1和R3，其中南极洲的风和南大洋的SST被推向观测值。此外，我们将诊断2019-2022年期间已知影响南极海冰的大气变化的相关模式，以进一步了解2022年海冰范围的损失。为了解决R2问题，我们计划扩展模型模拟，但不使用轻推，将模型用作预测模型（因为其2022年的初始条件将从轻推模拟结束时获取，并捕获观察状态的重要方面）。我们预计，如果目前上层海洋的热含量非常高，那么低海冰范围的情况可能会在2022-2024年持续下去，就像2016/2017年海冰范围创历史新低之后的2017-2019年一样。为了进一步解决R3问题，我们将使用项目团队开发的新型大气热传输计算来比较观测和模型模拟。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

SIPN South: six years of coordinated seasonal Antarctic sea ice predictions

• DOI: 10.3389/fmars.2023.1148899
• 发表时间: 2023-05
• 作者: F. Massonnet;S. Barreira;A. Barthélemy;R. Bilbao;E. Blanchard‐Wrigglesworth;E. Blockley;D. Bromwich;M. Bushuk;Xiaoran Dong;H. Goessling;W. Hobbs;D. Iovino;Woo-Sung Lee;Cuihua Li;W. Meier;W. Merryfield;E. Moreno‐Chamarro;Y. Morioka;Xuewei Li;B. Niraula;A. Petty;A. Sanna;Mariana Scilingo;Qi Shu;M. Sigmond;Nico Sun;S. Tietsche;Xingren Wu;Qinghua Yang;X. Yuan

The Largest Ever Recorded Heatwave—Characteristics and Attribution of the Antarctic Heatwave of March 2022

有记录以来最大的热浪——2022 年 3 月南极热浪的特征和归因

• DOI: 10.1029/2023gl104910
• 发表时间: 2023
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Blanchard‐Wrigglesworth, Edward;Cox, Tyler;Espinosa, Zachary I.;Donohoe, Aaron
• 通讯作者: Donohoe, Aaron

Winds and Meltwater Together Lead to Southern Ocean Surface Cooling and Sea Ice Expansion

风和融水共同导致南大洋表面冷却和海冰膨胀

• DOI: 10.1029/2023gl105948
• 发表时间: 2023
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Roach, Lettie A.;Mankoff, Kenneth D.;Romanou, Anastasia;Blanchard‐Wrigglesworth, Edward;Haine, Thomas W. N.;Schmidt, Gavin. A.
• 通讯作者: Schmidt, Gavin. A.