Assessing simulations of Southern Hemisphere tropospheric jet, meridional overturning circulation of the Southern Ocean and carbon uptake

评估南半球对流层急流、南大洋经向翻转环流和碳吸收的模拟

基本信息

批准号：
NE/J005339/1
负责人：
Emily Shuckburgh
金额：
$ 11.64万
依托单位：
British Antarctic Survey
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ005339%2F1
关键词：
Assessing simulations Southern Hemisphere tropospheric

项目摘要

Of the carbon dioxide emissions human activities generate each year, only about half stay in the atmosphere. The rest are taken up by the land and the oceans, in approximately equal measure. At present the Southern Ocean that encircles Antarctica accounts for just under half of the total ocean uptake. Were it not to do so, carbon dioxide levels in the atmosphere would increase at a significantly faster rate than we currently observe. The world's oceans are connected by a vast, slow circulation system with water sinking in the North Atlantic, travelling southward, and then rising to the surface in the Southern Ocean. When it reaches the surface, this water is able to exchange carbon dioxide with the atmosphere, before the circulation dips below the surface again, locking the carbon dioxide in the ocean, and returns north. If that circulation were to change, the carbon uptake of the Southern Ocean would change. So a key question to scientists to answer is, will climate change invoke changes to the overturning circulation of the Southern Ocean? If the answer is yes, then this could change the amount of carbon dioxide in the atmosphere and act as a strong feedback on climate change. Concern has been raised recently because some observations have indicated that indeed the Southern Ocean is taking up less carbon dioxide than we would have historically expected given the current atmospheric carbon dioxide concentrations.So how might climate change be impacting the Southern Ocean overturning circulation? Strong winds blow around Antarctic over the Southern Ocean. The winds directly drive a circulation that is directed northward at the surface. They also indirectly drive a circulation in the opposite direction, i.e. southward at the surface, via their influence on the generation of ocean storms, known as "eddies". The resultant circulation, which is directed northward at the surface, is a subtle balance of these opposing circulations. The winds have been observed to increase in recent decades. Two changes to the atmosphere are thought to have instigated the change in the winds, both of which have human cause: the increase in greenhouse gases in the atmosphere and the decrease in ozone in the stratosphere. It is reasonable to ask therefore whether the carbon uptake of the Southern Ocean might be influenced in the future by changes to the atmospheric concentration of greenhouse gases and by the recovery of the ozone layer. Computer models used to project future climate can only address this question if they are able to properly represent the different physical processes in the atmosphere and ocean that link the atmospheric composition to ocean carbon uptake via the Southern Ocean winds. This project aims to evaluate the representation of these processes in the latest generation of models that will be used as a basis for the next IPCC report.

人类活动每年产生的二氧化碳排放量中，只有大约一半留在大气中。其余部分被陆地和海洋占据，比例大致相等。目前，环绕南极洲的南大洋占海洋总吸收量的近一半。如果不这样做，大气中二氧化碳含量的增加速度将比我们目前观察到的要快得多。世界上的海洋由一个巨大而缓慢的循环系统连接起来，水在北大西洋下沉，向南流动，然后上升到南大洋的表面。当它到达地表时，这些水能够与大气交换二氧化碳，然后环流再次下降到地表以下，将二氧化碳锁定在海洋中，然后返回北方。如果环流发生变化，南大洋的碳吸收就会发生变化。因此，科学家需要回答的一个关键问题是，气候变化是否会引起南大洋翻转环流的变化？如果答案是肯定的，那么这可能会改变大气中二氧化碳的含量，并对气候变化起到强烈的反馈作用。最近引起了人们的关注，因为一些观测表明，考虑到当前大气二氧化碳浓度，南大洋吸收的二氧化碳确实比我们历史上预期的要少。那么，气候变化可能如何影响南大洋翻转环流呢？强风在南极洲周围吹过南大洋。风直接驱动地表向北的环流。它们还通过影响海洋风暴（称为“涡流”）的产生，间接驱动相反方向的环流，即地表向南。由此产生的环流在地表指向北，是这些相反环流的微妙平衡。据观察，近几十年来风力有所增强。人们认为大气的两种变化引发了风的变化，这两种变化都有人为原因：大气中温室气体的增加和平流层中臭氧的减少。因此，有理由提出这样的问题：未来南大洋的碳吸收是否会受到大气中温室气体浓度的变化和臭氧层的恢复的影响。用于预测未来气候的计算机模型只有能够正确表示大气和海洋中的不同物理过程（将大气成分与南大洋风吸收的海洋碳联系起来）才能解决这个问题。该项目旨在评估这些过程在最新一代模型中的表现，该模型将用作下一次 IPCC 报告的基础。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Assessment of Southern Ocean water mass circulation and characteristics in CMIP5 models: Historical bias and forcing response

DOI：
10.1002/jgrc.20135
发表时间：
2013-04
期刊：
Journal of Geophysical Research
影响因子：
0
作者：
J. Sallée;E. Shuckburgh;N. Bruneau;A. Meijers;T. Bracegirdle;Zhaomin Wang;T. Roy
通讯作者：
J. Sallée;E. Shuckburgh;N. Bruneau;A. Meijers;T. Bracegirdle;Zhaomin Wang;T. Roy

Assessment of Southern Ocean mixed-layer depths in CMIP5 models: Historical bias and forcing response