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Southern OceaN optimal Approach To Assess the carbon state, variability and climatic Drivers (SONATA)

南大洋评估碳状态、变异性和气候驱动因素的最佳方法 (SONATA)

基本信息

批准号：
NE/P021298/1
负责人：
Andrew Watson
金额：
$ 35.31万
依托单位：
UNIVERSITY OF EXETER
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FP021298%2F1
关键词：
Southern OceaN optimal Approach Assess

项目摘要

The Southern Ocean (SO) is the most exciting and extreme region of the world ocean, with the strongest winds, coldest temperatures, and most intense storms. It is believed also to be among the largest 'sink' for atmospheric CO2, accounting for about one third of the uptake of CO2 by the global ocean and nearly one tenth of the global emissions of CO2 on average each year. Thus the evolution of the SO carbon sink has the potential to alter the rate and extent of climate change.In spite of its importance, we don't know the state, variability, or climatic drivers of the contemporary SO carbon sink and there is much controversy over its recent evolution. The climate of the SO has been changing over recent decades: in particular, winds have intensified, (attributed in part to the depletion of stratospheric ozone and in part to increasing temperature gradients arising from climate change), ocean acidification is occurring, and there is a long term decline in krill stocks. These effects take place on top of large natural variability and poorly quantified climatic trends.SONATA will achieve a step change in our understanding of the contemporary SO carbon sink by delivering new data and new insights, integrating observations from the ocean, from the atmosphere, and model results. We will develop three complementary streams of research, an 'Oceanic', an 'Atmospheric', and a 'Processes and drivers' view, and will bring them together using advanced mathematical frameworks to provide a single assessment with multiple constraints and reduction of uncertainties.The Oceanic view will use existing and new observations of ocean carbon. We will undertake a new calibration experiment to better assess the large number of pH measurements now being made by about 200 sophisticated profiling floats introduced by the US SOCCOM programme. These have the potential to greatly increase the number of observations that can be used to calculate air-sea CO2 fluxes, but only if adequately calibrated. In addition we will develop and use a new technique to construct estimates of the seasonal and temporal evolution of the air-sea flux, using a model of the upper water column constrained with available hydrographic and carbon-system observations. The Atmospheric view will collect new atmospheric CO2 data in remote SO locations comprising Halley Station (75S), the Falkland Islands (51S), and aboard the BAS research ship James Clark Ross; new atmospheric O2 data will come from a ship track that repeats a SO transect every 8 weeks, as well as from Halley Station in coastal Antarctica. Using these data and an inverse framework approach, SONATA will provide an independent assessment of the SO carbon sink, which will deliver particularly on the geographic distribution of the changes, with O2 data helping to inform the drivers.The Processes and drivers view will use two climate-scale carbon models and a series of hindcast simulations to identify the relative contributions of (a) atmospheric CO2 concentration, (b) natural climate variability, (c) climate change, and (d) stratospheric ozone depletion to recent SO carbon trends and variability. Ocean and atmosphere observations, including new data from SONATA and SOCCOM, will be used to optimise the model and validate the results. Idealised forcing with climate models will provide the 'fingerprints' of climatic drivers that are needed to understand the observed patterns of change.Finally the three streams of research will be integrated using a Bayesian fusion mathematical approach that considers the strengths and weaknesses of each stream of information and minimises the joint uncertainty. The SO ocean carbon sink will be assessed annually in this way. We will then test the added value of including new streams of observations in the future, including from floats, gliders, drifters, Autonomous Surface Vehicles, additional ground-based observations and satellite CO2 data.

南大洋（SO）是世界海洋中最令人兴奋和极端的区域，拥有最强的风、最冷的温度和最强烈的风暴。它也被认为是最大的大气二氧化碳“汇”之一，平均每年约占全球海洋吸收二氧化碳的三分之一，占全球二氧化碳排放量的近十分之一。因此，SO 碳汇的演变有可能改变气候变化的速度和程度。尽管它很重要，但我们不知道当代 SO 碳汇的状态、变异性或气候驱动因素，并且对其最近的演变存在很多争议。近几十年来，南太平洋地区的气候一直在变化：特别是风力增强（部分原因是平流层臭氧消耗，部分原因是气候变化引起的温度梯度增加），海洋酸化正在发生，磷虾种群长期下降。这些影响是在巨大的自然变率和难以量化的气候趋势的基础上产生的。SONATA 将通过提供新数据和新见解，整合来自海洋、大气的观测结果和模型结果，实现我们对当代 SO 碳汇的理解的一步改变。我们将开发三个互补的研究流，“海洋”、“大气”和“过程和驱动因素”视图，并将使用先进的数学框架将它们结合在一起，以提供具有多重约束和减少不确定性的单一评估。海洋视图将使用现有的和新的海洋碳观测结果。我们将进行一项新的校准实验，以更好地评估目前由美国 SOCCOM 计划引入的约 200 个复杂的分析浮标进行的大量 pH 测量。这些有可能大大增加可用于计算海气二氧化碳通量的观测数量，但前提是经过充分校准。此外，我们将开发并使用一种新技术来构建海气通量的季节和时间演变的估计，使用受现有水文和碳系统观测约束的上层水柱模型。大气视图将收集偏远 SO 地点的新大气 CO2 数据，包括哈雷站 (75S)、福克兰群岛 (51S) 以及 BAS 研究船 James Clark Ross 上的数据；新的大气 O2 数据将来自每 8 周重复一次 SO 横断面的船舶轨迹以及南极洲沿海的哈雷站。利用这些数据和逆向框架方法，SONATA 将提供对 SO 碳汇的独立评估，特别是变化的地理分布，其中 O2 数据有助于为驱动因素提供信息。过程和驱动因素视图将使用两个气候规模碳模型和一系列事后模拟来确定 (a) 大气二氧化碳浓度、(b) 自然气候变率、(c) 气候变化和 (d) 平流层的相对贡献臭氧消耗到最近的二氧化硫碳趋势和变化。海洋和大气观测，包括来自 SONATA 和 SOCCOM 的新数据，将用于优化模型并验证结果。气候模型的理想化强迫将提供理解观测到的变化模式所需的气候驱动因素的“指纹”。最后，将使用贝叶斯融合数学方法整合这三个研究流，该方法考虑每个信息流的优点和缺点，并最大限度地减少联合不确定性。 SO海洋碳汇每年都会以这种方式进行评估。然后，我们将测试未来纳入新观测流的附加值，包括来自浮标、滑翔机、漂流器、自主地面车辆、额外的地面观测和卫星二氧化碳数据。