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The role of oceans in climate asymmetries

海洋在气候不对称中的作用

基本信息

批准号：
1850900
负责人：
Kyle Armour
金额：
$ 35.89万
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：
2019
资助国家：
美国
起止时间：
2019-04-01 至 2023-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1850900&HistoricalAwards=false
关键词：
role oceans climate asymmetries

项目摘要

The oceans are responsible for a range of scientifically interesting and societally relevant asymmetries in Earth's climate. Moreover, the ocean's long timescales and diverse regional circulations impose strong constraints on the patterns of surface and subsurface warming under greenhouse-gas forcing. In turn, oceans mediate the rate and magnitude of global warming through (i) storage of anomalous heat at depth and (ii) the coupling between surface warming patterns and atmospheric radiative feedbacks, which governs the evolution of global climate sensitivity. Insights into the role of oceans in climate have come from idealized coupled global climate model (GCM) experiments wherein different ocean circulations and climates are induced by prescribing distinct continental geometries. This project is to examine the role of large scale oceanic circulation in the earth's climate system in simplified geometries and with cloud feedbacks. Different idealized continental configurations will be considered. This work improves upon previous efforts that have used ocean-only models or coupled models that did not include cloud-feedbacks. This work would support a female graduate student, an assistant professor to advise the research, and a part-time software engineer to assist in technical aspects of computing and modeling. The graduate student would gain valuable experience in teaching and communicating climate science. The idealized nature of results from this project would make them valuable additions to undergraduate and graduate courses. Tools developed for the purposes of designing idealized continental (or bathymetric) geometries in the coupled model will be made widely available to the community through both GitHub and, eventually, within NCAR's Community Earth System Model (CESM) idealized ocean model hierarchy.This project improves on previously idealized, coupled modeling framework in three key ways: (i) By employing state-of-the-art model components that, importantly, represent realistic cloud feedbacks which were previously neglected; (ii) By performing simulations with novel continental geometries and with varying planetary rotation rates; and (iii) By performing carbon dioxide forcing simulations with a range of background ocean circulation regimes induced by those distinct continental geometries. These model experiments are designed to answer key outstanding questions about the role of oceans in climate and climate change. The work will lead to improved understanding of the conditions by which large-scale ocean circulations arise and in turn govern: (i) large-scale asymmetries in climate; (ii) geographic patterns of climate change; and (iii) the rate and magnitude of global warming. In particular, it will provide deeper knowledge of the specific dynamics by which the oceans and atmosphere affect pole-to-equator temperature gradients; meridional heat transport and its partitioning between oceans and atmosphere; freshwater transport; tropical rainfall patterns; and localization of deep-water formation and meridional overturning. The work could also provide a physical theory for why GCMs predict increasing climate sensitivity under greenhouse-gas forcing, thus improving our understanding of one of the major uncertainties in climate projection. Evaluating the key role of clouds and cloud feedbacks in contributing to these features will be a focus throughout.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.

海洋造成了地球气候中一系列具有科学意义和社会相关性的不对称性。此外，海洋的长时间尺度和多样化的区域环流对温室气体强迫下的地表和地下变暖模式产生了强烈的约束。反过来，海洋通过（i）在深处储存异常热量以及（ii）地表变暖模式与大气辐射反馈之间的耦合来调节全球变暖的速度和幅度，从而控制全球气候敏感性的演变。对海洋在气候中的作用的深入了解来自理想化耦合全球气候模型（GCM）实验，其中不同的海洋环流和气候是通过规定不同的大陆几何形状而引起的。该项目旨在以简化的几何形状和云反馈来研究大规模海洋环流在地球气候系统中的作用。将考虑不同的理想化大陆配置。这项工作改进了之前使用仅海洋模型或不包括云反馈的耦合模型的工作。这项工作将支持一名女研究生、一名助理教授为研究提供建议，以及一名兼职软件工程师协助计算和建模的技术方面。研究生将在气候科学的教学和交流方面获得宝贵的经验。该项目结果的理想化性质将使它们成为本科生和研究生课程的宝贵补充。为在耦合模型中设计理想化大陆（或测深）几何形状而开发的工具将通过 GitHub 以及最终在 NCAR 的社区地球系统模型 (CESM) 理想化海洋模型层次结构中向社区广泛提供。该项目通过三个关键方式改进了之前理想化的耦合建模框架：(i) 通过采用最先进的模型组件，重要的是，这些组件代表现实以前被忽视的云反馈； (ii) 通过新颖的大陆几何形状和不同的行星自转速率进行模拟； (iii) 通过对由这些独特的大陆几何形状引起的一系列背景海洋环流状况进行二氧化碳强迫模拟。这些模型实验旨在回答有关海洋在气候和气候变化中的作用的关键突出问题。这项工作将有助于更好地了解大规模海洋环流产生的条件，进而控制：（i）气候的大规模不对称；㈡气候变化的地理格局； (iii) 全球变暖的速度和程度。特别是，它将提供有关海洋和大气影响极地到赤道温度梯度的具体动力学的更深入的知识；经向热传输及其在海洋和大气之间的分配；淡水运输；热带降雨模式；以及深水地层和经向翻转的定位。这项工作还可以为为什么全球气候模型预测在温室气体强迫下气候敏感性增加提供一个物理理论，从而提高我们对气候预测中主要不确定性之一的理解。评估云和云反馈在促进这些功能方面的关键作用将是整个过程的重点。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点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

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Seasonality in Arctic Warming Driven by Sea Ice Effective Heat Capacity

海冰有效热容驱动的北极变暖的季节性

DOI：
10.1175/jcli-d-21-0626.1
发表时间：
2022
期刊：
Journal of Climate
影响因子：
4.9
作者：
Hahn, Lily C.;Armour, Kyle C.;Battisti, David S.;Eisenman, Ian;Bitz, Cecilia M.
通讯作者：
Bitz, Cecilia M.

The Impact of Winds on AMOC in a Fully‐Coupled Climate Model

全耦合气候模型中风对 AMOC 的影响

DOI：
10.1029/2022gl101203
发表时间：
2022
期刊：
Geophysical Research Letters
影响因子：
5.2
作者：
Roach, Lettie A.;Blanchard‐Wrigglesworth, Edward;Ragen, Sarah;Cheng, Wei;Armour, Kyle C.;Bitz, Cecilia M.
通讯作者：
Bitz, Cecilia M.

Mechanisms of Low-Frequency Variability in North Atlantic Ocean Heat Transport and AMOC

北大西洋热传输和 AMOC 低频变化机制

DOI：
10.1175/jcli-d-20-0614.1
发表时间：
2021
期刊：
Journal of Climate
影响因子：
4.9
作者：
Oldenburg, Dylan;Wills, Robert C.;Armour, Kyle C.;Thompson, LuAnne;Jackson, Laura C.
通讯作者：
Jackson, Laura C.

Terrestrial Evaporation and Global Climate: Lessons from Northland, a Planet with a Hemispheric Continent