RAPID: Fine- and Microstructure Observations in Conjunction with a GEOTRACES Section along 40 degrees S in the Atlantic

该项目资助与英国资助的南大西洋沿着40 S的GEOTRACES A10部分一起采集和分析精细和微观结构数据。将使用垂直剖面和滑翔机平台的组合。 由此产生的数据将被用来估计区域diapycnal混合和isopycnal搅拌速率。 预计将有显着的区域变化，在潮汐，涡流，地形形态和平均地转流的变化作出反应。 辐射平衡方程将有助于对径向混合的估计，而等密度搅拌的估计将通过与已发表的标度的比较而得到信息。学术价值关于海洋热量、质量、动量、能量、位涡或被动示踪剂如何平衡的细节，存在着很大的不确定性，特别是在次中尺度，特别是关于非线性对波辐射的作用和内波对地转运动的作用。 拟议的工作将通过记录沿GEOTRACES A10剖面的精细和微观结构场沿着来解决这种不确定性，并将定量研究与更大空间和时间尺度上的变异性的关系和依赖性。 将测量的透圆混合率与基于辐射平衡方程的与区域内波气候相关的湍流产生的估计进行比较。等密度搅拌速率将与基于弱非线性和湍流分析的已发表的标度进行比较。更广泛的影响拟议研究的结果将有助于理解和预测全球气候变化和碳循环。 将努力直接支持GEOTRACES计划，因为该研究的重点是生物地球化学预算，取决于透圆混合和等密度搅拌速率。 该项目将提供这些数据的直接估计，并将协助解释。 它还将协助为用于预测海洋气候反应的大气环流模型制定和实施湍流混合和等密度搅拌参数化。 具体而言，来自微观结构观察的diapycnal混合和isopycnal搅拌的表征将由牛津大学的合作者在他们的一般循环模型模拟示踪剂运输。

This project funds the acquisition and analysis of fine- and microstructure data in conjunction with the UK funded GEOTRACES A10 section along 40S in the South Atlantic. A combination of vertical profiling and glider platforms will be used. The resulting data will be used to estimate regional diapycnal mixing and isopycnal stirring rates. It is anticipated that there will be significant regional variability in response to variations in tides, eddies, topographic morphology and mean geostrophic currents. Estimates of diapycnal mixing will be aided by radiation balance equations and estimates of isopycnal stirring will be informed by comparison to published scalings.Intellectual MeritThere is a great deal of uncertainty regarding the details of how oceanic budgets of heat, mass, momentum, energy, potential vorticity or passive tracers are balanced, particularly at the submesoscale and especially with regards to the roles of nonlinearity versus wave radiation and the role of internal waves versus geostrophic motions. The proposed work will address this uncertainty by documenting fine- and microstructure fields along the GEOTRACES A10 section and will quantitatively investigate the relationship to, and dependence upon, variability on larger spatial and temporal scales. Measured diapycnal mixing rates will be compared to radiation balance equation based estimates of turbulent production associated with the regional internal wave climate. Isopycnal stirring rates will be compared to published scalings based upon both weakly nonlinear and turbulent analyses.Broader ImpactsResults of the proposed research will contribute to the understanding and prediction of global climate change and the carbon cycle. Efforts will be in direct support of the GEOTRACES program as the biogeochemical budgets that are the focus of that study depend upon diapycnal mixing and isopycnal stirring rates. The project will provide direct estimates of these and will assist with the interpretation. It will also assist with the development and implementation of turbulent mixing and isopycnal stirring parameterizations for general circulation models used to predict the ocean climate response. Specifically, the characterization of diapycnal mixing and isopycnal stirring derived from the microstructure observations will be incorporated by collaborators at Oxford University in their general circulation model simulations of tracer transport.