What Controls the Variability of the Southern Ocean Productivity and Carbon Uptake?

由于我们对海洋生态系统对物理强迫、海洋运输和气候变化的反应的不完全理解，阻碍了南大洋生物生产力和相应的碳吸收量（包括化石燃料二氧化碳）的变化。该模型研究将解决三个主要问题：1)将气候动力学和生物生产联系起来的机制是什么？微量营养素铁限制的机制是什么？不同铁来源的相对重要性是什么？中尺度涡旋在区域碳和铁收支中的作用是什么？基于MIT海洋环流模式（MITgcm），来自南大洋状态估计的涡旋允许（1/60 x 1/60纬度；42深度）物理环流场将受到一个非常大的南大洋性质观测数据集的约束。模式模拟改进了来自大陆架的铁源，并包括大气中不断增加的分压（pCO2）与富含CO2的冷水体上涌之间的相互作用，将根据观测到的地表叶绿素和生物地球化学示踪剂的变化进行测试。这项研究应该能对最近和未来几年的碳和铁预算做出更真实的估计。该项目的教育方面将在佐治亚理工学院培训一名研究生和本科生实习生，学习地球系统建模。

The variability of the biological productivity and correspondingly the carbon uptake, including fossil fuel CO2, of the Southern Ocean are hampered by our incomplete understanding of the responses of the marine ecosystems to physical forcings, oceanic transport and climate change. This modeling study will address three main questions: i) what are the mechanism that link climate dynamics and biological production? ii) what are the mechanisms for micronutrient iron limitation and the relative importance of different iron sources? and iii) what are the roles of mesoscale eddies on regional carbon and iron budgets? Based on the MIT ocean general circulation model (MITgcm), eddy permitting (1/60 x 1/60 lat lon; 42 depth levels) physical circulation fields from the Southern Ocean State Estimate will be constrained by a very large observational data set of Southern ocean properties. Model simulations, with improved representations of iron sources from continental shelves, and including the interplay between increasing partial pressure (pCO2) in the atmosphere and upwelling of cold CO2 rich waters, will be tested against the observed variability of surface chlorophyll and biogeochemical tracers. This research should yield a more authentic estimate of the carbon, and iron budgets for recent and future years. Educational aspect of the project will train a graduate student and undergraduate student interns in earth-system modeling at Georgia Institute of Technology.