Role of Physical Processes in the Southern Ocean CO2 Sink

CMIP 5，耦合模式相互比较项目（第5阶段），促进一套标准的地球系统模式气候模拟，以便：i）评估我们的模式在模拟最近过去的气候方面的现实程度，ii）在两个时间尺度上提供未来气候变化的预测，一个是近期，（到2035年左右）和一个长期（到2100年及以后），以及iii）了解造成模型预测差异的一些因素，包括量化一些关键反馈，如涉及云和碳循环的反馈。该项目旨在分析CMIP 5模式输出，以评估南大洋影响表层水pCO2变化和海气CO2吸收的物理过程的影响，将进行系统的模式相互比较，以解决三个主要问题：1）整个南大洋表层海洋pCO2的纬向变化有多显著，因此，在南大洋其他地区，紧急情况管理措施的德雷克通道的情况有多大的代表性？2)南大洋表面沃茨中pCO2的增加率是否与上升到锋面以南洋面的溶解无机碳（DIC）总量的增加一致？3)什么物理过程可以解释在八个可用的ESM中的一半中发现的极锋附近的地表水pCO2浓度过高？增加对未来气候变化的了解符合美国的利益。

CMIP5, the Coupled Model Intercomparison Project (Phase 5) promotes a standard set of earth system model climate simulations in order to: i) evaluate how realistic our models are in simulating climate of the recent past, ii) provide projections of future climate change on two time scales, one near term (out to about 2035) and one long term (out to 2100 and beyond), and iii) understand some of the factors responsible for differences in model projections, including quantifying some key feedbacks such as those involving clouds and the carbon cycle. This project aims to analyse CMIP5 model output to assess the impacts of physical processes in the Southern Ocean that influences surface water pCO2 variation, and air-sea CO2 uptake.Systematic model intercomparisons will be carried out to tackle three main questions: 1) How significant are the zonal variationsin surface ocean pCO2 throughout the entire Southern Ocean, hence, how representative are conditions in Drake Passage of ESMs in other areas of the Southern Ocean? 2) Does the rate of pCO2 increase in the surface waters of the Southern Ocean concur with the increase of total Dissolved Inorganic Carbon (DIC) upwelled to the ocean surface south of the fronts? 3) What physical processes can explain the excessive surface water pCO2 concentrations found near the Polar Front in half of the eight available ESMs?Increased knowledge of future climate change is in the interest of the US.