Understanding the Causes of the Excessive Cold Tongue in the National Center for Atmospheric Research Community Climate System Model (NCAR CCSM)

赤道太平洋冷舌在海洋-大气耦合系统的热碳平衡中起着重要作用。控制冷舌的过程和反馈还没有被很好地理解，而且耦合的气候模式，例如社区气候系统模式（CCSM）不能正确地模拟它。PI假设，耦合gcm在赤道太平洋发展过度冷舌的趋势至少部分是由于模式大气对该地区海温变化的微弱调节作用。更具体地说，耦合模式中的大气净反馈（辐射反馈加上动力反馈）比观测中的负反馈要小。由于地表加热对海表温度变化的约束作用较弱，导致了海洋动力效应的“过表达”，导致耦合模式中出现了过度冷舌。PI将进行一个试点项目来验证他的假设，通过检查其他（除了CCSM）遭受过度冷舌的主要耦合模式是否也缺乏相应的赤道太平洋模式大气的足够强的调节作用。第一步将通过PI将其反馈分析扩展到参与大气模式比对项目（AMIP）的所有大气模式，并通过检查提交给耦合模式比对项目（CMIP）的相应耦合运行来实现。预计该项目将产生更广泛的影响，包括对感兴趣的公民以及未来科学家的学习、教育和培训做出贡献，并改进气候预测模型，这将对社会有价值。

The equatorial Pacific cold-tongue plays a fundamental role in the heat and carbon balance of the coupled ocean-atmosphere system. The processes and feedbacks that control the cold tongue are not well understood and coupled climate models, e.g., the Community Climate System Model (CCSM), do not properly simulate it. The PI has hypothesized that the tendency for the coupled GCMs to develop an excessive cold-tongue in the equatorial Pacific is at least in part due to a weak regulating effect from the model atmosphere on SST changes in that region. More specifically, the net atmospheric feedback (radiative plus dynamical feedbacks) in the coupled models is less negative than in the observations. The corresponding weaker constraining effect on the SST change by the surface heating then results in an "over-expression" of the effect of ocean dynamics, leading to the development of an excessive cold-tongue in the coupled model. The PI will conduct a pilot project to test his hypothesis by checking whether other (than CCSM) major coupled models that suffer from an excessive cold-tongue also lack a sufficiently strong regulating effect from their corresponding model atmosphere over the equatorial Pacific. This first step will be achieved by the PI extending his feedback analysis to all the atmospheric models participating with the Atmospheric Model Intercomparison Project (AMIP) and by examining their corresponding coupled runs submitted to the Coupled Model Intercomparison Project (CMIP). The broader impacts expected from this project include, contributions to the learning, education, and training of interested citizens as well as future scientists and improvements in climate prediction models, which would be of value to society.