Collaborative Research: An Ocean Tale of Two Climates: Modern and Last Glacial Maximum

合作研究：两种气候的海洋故事：现代和末次盛冰期

• 批准号: 1536515
• 负责人: Raffaele Ferrari
• 金额: $ 42.4万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2021-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536515&HistoricalAwards=false
• 关键词: Collaborative; Research; Ocean; Tale; Two

The paleoclimate record shows that the climatic changes between glacial and interglacial periods were associated with large swings in atmospheric carbon dioxide concentrations. It is reasonably well established that the ocean was a major sink for the carbon lost by the atmosphere during the cold glacial spells. Furthermore observations suggest that the ocean water masses underwent major rearrangements during these periods. The chain of events by which the ocean state and circulation changed, however, is still unknown and represents a roadblock in our understanding of the great redistributions of carbon that occurred during glacial cycles. Our lack of a quantitative understanding of the changes in ocean circulation and atmospheric carbon dioxide during glacial climates represents a serious deficiency in our understanding of the climate system and shakes our confidence in projections of future climate. The goal of our project is to make progress towards a more quantitative understanding of glacial climates by combining emerging theories of the deep ocean circulation and observations. The project will also provide ideal training for a student and a postdoc.This project attempts to draw a quantitative picture of the differences in the ocean state and circulation between the present and the Last Glacial Maximum, which is consistent both with our current theoretical understanding of the deep ocean circulation, as well as with available modern and paleo observations. To achieve this goal, the scientists will use a combination of forward and inverse modeling. The forward models will develop a mechanistic understanding of the circulation, with a focus on the changes between the present and the Last Glacial Maximum, while the inverse models will test the consistency of the emerging picture with observations. The study builds on a hypothesis that argues that the permanent (summer) sea ice extent around Antarctica exerts a strong control on the Southern Ocean buoyancy fluxes and in turn on the deep ocean circulation. This qualitative hypothesis will be developed into a quantitative "diagnostic theory" of the deep ocean circulation and carbon storage during the Last Glacial Maximum. The research has three main parts: (1) Improving the mechanistic understanding of the present-day deep ocean circulation and stratification, (2) Analyzing the impact of increased permanent sea ice extent on the deep circulation while establishing the consistency of the emerging picture with available observational data. (3) Investigating the connection between the modified ocean circulation/stratification and the changes in ocean carbon storage.

古气候记录表明，冰川时期和冰川间期之间的气候变化与大气二氧化碳浓度的大幅波动有关。相当很好的确定，海洋是冷冰川咒语中大气丢失的碳的主要水槽。此外，观察结果表明，在这些时期，海水进行了重大重排。但是，海洋国家和循环发生变化的事件链仍然未知，这代表了我们对冰川周期中发生的碳重新分配的理解。我们对冰川气候期间海洋循环和大气二氧化碳的变化的定量理解缺乏认识，这是我们对气候系统的理解的严重缺陷，并使我们对未来气候预测的信心充满信心。我们项目的目的是通过结合新兴的深海循环和观察理论来实现对冰川气候的进步。该项目还将为学生和博士后提供理想的培训。该项目试图对海洋状态的差异以及当前和最后一次冰川最大值之间的差异进行定量描述，这既与我们当前对深海循环的理论理解以及现代现代和古观测。为了实现这一目标，科学家将结合前进和反向建模。正向模型将对循环产生一种机械理解，重点是当下和最后一个冰川最大值之间的变化，而反向模型将测试新兴图片与观测值的一致性。 这项研究以一个假设为基础，该假设认为，南极围绕的永久（夏季）海冰范围对南部海洋浮力通量产生了强烈的控制，进而对深海循环进行了强烈的控制。在最后一次冰川最大值期间，该定性假设将发展为深海循环和碳储存的定量“诊断理论”。这项研究有三个主要部分：（1）提高对当今深海循环和分层的机械理解，（2）分析永久性海冰范围对深层循环的影响，同时通过可用的观察数据确定新兴图片的一致性。 （3）研究经过改进的海洋循环/分层与海洋碳储存变化之间的联系。