The South Atlantic / Southern Ocean carbon sink: Is it significant, and is it changing over time?

南大西洋/南大洋碳汇：是否重要，是否随时间变化？

基本信息

批准号：
NE/F005733/1
负责人：
Andrew Manning
金额：
$ 50.43万
依托单位：
University of East Anglia
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FF005733%2F1
关键词：
South Atlantic Southern Ocean carbon

项目摘要

This project is designed to determine how much carbon dioxide (CO2) is absorbed by the South Atlantic and neighbouring Southern Ocean, and how important this is in the global picture. We will achieve this by measurement of atmospheric CO2 and related species at several key islands, and on a commercial ship, and by use of the atmospheric data in modelling studies to determine the uptake (amount absorbed) and whether it is changing over time. Understanding the uptake of CO2 by the oceans is essential, if we are to meet the challenge of understanding global warming by greenhouse gases. This is because, of the CO2 we produce by burning fossil fuels, only about half stays in the atmosphere and contributes to global warming. Most of the remainder is taken up by the global oceans, which, while not contributing to global warming, does contribute to the harmful acidification of the oceans. But exactly how much is taken up, in which oceans, and how this uptake might change in a warming climate is unclear. One important region with the least clarity is the South Atlantic Ocean. By determining CO2 uptake of the South Atlantic and neighbouring Southern Ocean, this project will provide new information that will improve models of the global CO2 cycle. Our work will also contribute to answering the question if Southern Ocean CO2 uptake is changing under global warming. If it is, the implications are serious, and will affect future international emissions negotiations. Although CO2 is measured in seawater in the South Atlantic (for example by British Antarctic Survey), there are virtually no measurements of CO2 in the air above the region. This is because the inhabited islands are UK-owned, and the UK does not participate in international efforts to monitor atmospheric CO2, which are coordinated by the UN's Global Atmosphere Watch programme. Measuring CO2 from the atmosphere is perhaps more important, and more revealing, than measuring from the ocean. The reason is that the atmosphere mixes much faster than the ocean, and so measurements from any given station are representative of a region covering hundreds or even thousands of square kilometres, compared to only a few square kilometres for ocean water measurements. Our measurements will assess the differences in CO2 as air blows across the ocean and CO2 is absorbed by the water. CO2 varies greatly across the planet, both by latitude and by season, just as temperature varies. Our measurements will be carried out by a mixture of continuous observations and canister sampling. Continuous measurement of CO2 will be made at Ascension Island, near the equator, and at Falkland Islands, around 50S. CO2 will also be measured by canister sampling at these and three other UK islands. In addition, O2 concentrations and the isotope 13C in CO2 will be measured from the canister samples. Measuring these additional species tells us about the non-photosynthetic CO2, both fossil-fuel emissions and ocean uptake. Finally, we will also measure CO2 and O2 continuously onboard a commercial ship travelling across the Atlantic, to complement the data from the fixed stations. To interpret our measurements, we will carry out modelling studies. Presently, models based on ocean-water measurement seem to give different answers from the models based on the sparse atmospheric data. It is possible that CO2 uptake may change as the oceans warm, but much more evidence is needed. Our modelling studies will address these problems and will provide a much better understanding of how much CO2 is being taken up into the water in the region. Our work will help improve knowledge of one of the most poorly understood parts of the global carbon budget, the Southern Ocean. Better understanding of the atmospheric side of the equation will also be very helpful to oceanographers, because the South Atlantic and neighbouring Southern Ocean are a great global weather factory, and a key turning point of the ocean circulation system.

该项目旨在确定南大西洋和邻近的南大洋吸收了多少二氧化碳（CO2），以及在全球情况中的重要性。我们将通过在几个关键岛屿以及商业船上的大气二氧化碳和相关物种的测量以及在建模研究中使用大气数据来确定吸收（吸收量）以及它是否随着时间的推移而变化，这将实现这一目标。如果我们要面对了解温室气体的全球变暖的挑战，那么了解海洋对二氧化碳的吸收至关重要。这是因为，在我们通过燃烧化石燃料生产的二氧化碳中，只有大约一半留在大气中，并有助于全球变暖。其余的大部分是由全球海洋所占据的，尽管没有促成全球变暖，但确实有助于海洋的有害酸化。但是，尚不清楚在温暖的气候中占用多少海洋以及在温暖气候下可能会改变这种吸收的程度。最清晰的一个重要地区是南大西洋。通过确定南大西洋和邻近南洋的二氧化碳吸收，该项目将提供新的信息，以改善全球二氧化碳周期的模型。我们的工作还将有助于回答南方海洋二氧化碳在全球变暖下的摄取是否发生变化的问题。如果是这样的话，其影响是严重的，并且会影响未来的国际排放谈判。尽管在南大西洋的海水中测量了二氧化碳（例如，通过英国南极调查），但该地区上方的空气中几乎没有二氧化碳的测量值。这是因为居住的岛屿是英国拥有的，并且英国不参加国际努力监测大气二氧化碳的努力，大气二氧化碳是由联合国全球大气观察计划协调的。从大气中测量二氧化碳也许比从海洋中测量的更重要，更具启发性。原因是大气混合的速度比海洋要快得多，因此任何给定站点的测量都代表了覆盖数百甚至数千平方公里的区域，而海水测量只有几平方公里。我们的测量结果将评估二氧化碳的差异，因为横跨海洋和二氧化碳被水吸收。二氧化碳在整个星球上的差异很大，无论温度变化而变化。我们的测量将通过连续观测和罐采样的混合物进行。二氧化碳的连续测量将在赤道附近的Ascension Island和Falkland群岛进行大约50年代。二氧化碳还将通过在英国和其他三个英国岛上进行罐采样来衡量。另外，将从罐样品中测量二氧化碳中的O2浓度和同位素13C。测量这些其他物种向我们介绍了化石燃料排放量和海洋吸收的非光合合成二氧化碳。最后，我们还将连续测量二氧化碳和O2在跨大西洋旅行的商业船上，以补充固定站的数据。为了解释我们的测量值，我们将进行建模研究。目前，基于海水测量的模型似乎基于稀疏大气数据给出了模型的不同答案。随着海洋的温暖，二氧化碳吸收可能会发生变化，但需要更多证据。我们的建模研究将解决这些问题，并将更好地了解该地区水中的二氧化碳数量。我们的工作将有助于提高对全球碳预算中南大洋最了解部分之一的了解。更好地了解方程式大气方面也将对海洋学家非常有帮助，因为南大西洋和邻近的南大洋是一个很棒的全球天气厂，也是海洋循环系统的关键转折点。