Collaborative Research: The Pacific Meridional Mode and El Niño-Southern Oscillation (ENSO)

本研究旨在加深对太平洋“经向模”(MM)的结构、动力学和影响及其对厄尔尼诺-南方涛动(ENSO)季节性的影响的认识。尽管太平洋MM对热带年际和年代际气候变率的解释比ENSO小，但它在热带年际和年代际气候变率中起着重要作用：观测和模拟研究都提供了令人信服的证据，证明MM有助于启动ENSO变率，可能强烈影响ENSO季节性，并对热带类似ENSO的年代际变率的时空结构做出贡献。因此，需要更好地了解促成太平洋MM变率的基本物理过程及其与ENSO的联系。这项研究解决了关于MM可变性及其与ENSO的关系的三个主要问题：Q1)我们能否描述太平洋MM的详细结构和动力学，包括它与ENSO的联系，在自然界和当代的大气环流模式中？Q2)平均状态和季节周期如何影响太平洋MM？是什么过程导致了太平洋MM变率的季节性及其与ENSO的关系？问题3)把太平洋MM和ENSO联系起来的动力机制是什么？MM变率的季节性如何影响ENSO对季节周期的位相锁定？这项研究将包括对政府间气候变化专门委员会第四次评估报告中的观测数据和模式数据的分析；开发一系列线性耦合模式，以加强对影响MM变异性的主要物理过程的了解；这项研究的更广泛的影响包括：通过与气候预测界的联系(通过共同的研究兴趣、私营部门的个人专业活动以及提议在一次重大会议上举行一次会议)，培训两名研究生，开发和测试最终将分发给更广泛的科学界的工具，以及私营部门的持续努力，将研究与教育结合起来，并鼓励其研究环境中的族裔和性别多样性。

This research is aimed at enhanced understanding of the structure, dynamics, and impacts of the Pacific "meridional mode" (MM), as well as its influence on El-Nino-Southern Oscillation (ENSO) seasonality. Despite explaining less variance than ENSO, the Pacific MM plays an important role in tropical interannual and decadal climate variability: both observational and modeling studies provide compelling evidence that the MM assists in initiating ENSO variability, may strongly influence ENSO seasonality, and contributes to the spatial and temporal structure of tropical ENSO-like decadal variability. Thus, a better understanding of the underlying physical processes that contribute to MM variability in the Pacific, as well as its link with ENSO, is needed. The research addresses three major questions concerning MM variability and its relationship with ENSO: Q1) Can we characterize the detailed structure and dynamics of the Pacific MM, including its link with ENSO, in nature and in the current generation of general circulation models? Q2) How does the mean state and seasonal cycle influence the Pacific MM? What processes contribute to the seasonality of Pacific MM variability and its relationship to ENSO? Q3) What are the dynamical mechanisms that link the Pacific MM to ENSO? How does the seasonality of MM variability affect ENSO's phase locking to the seasonal cycle? The research will include analyses of observational data, and model data from the Intergovernmental Panel on Climate Change 4th Assessment Report; the development of a series of linear coupled models that enhance understanding of the dominant physical processes that affect MM variability; and a series of modeling studies using the National Center for Atmospheric Research (NCAR) atmospheric general circulation models (AGCMs) coupled with two different ocean models Broader Impacts: The broader impacts of this research include its societal contribution through links with the climate prediction community (through common research interests, individual professional activities by the PIs, and a proposed session at a major meeting), training of two graduate students, the development and testing of tools that will eventually be distributed to the broader scientific community, and by continuing efforts by the PIs to integrate research and education, and to encourage ethnic and gender diversity in their research environments.