Collaborative Research: The Role of Basin Modes in Pacing Pacific Decadal Variability

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。本项目将探讨罗斯比盆地模态在太平洋年代际变率（PDV）中起重要作用的假设。斜压罗斯比海盆模态是海洋的自然振荡，具有非常大的空间尺度和长达十年或更长时间的周期，使它们对了解气候变率具有明显的兴趣。拟议的工作将包括三个主要任务。第一项任务将是系统地确定在(i)盆地几何形状和底部地形，（ii）背景环流和分层，以及（iii）罗斯比波不稳定性的综合影响下盆地模式的周期、衰减率和空间模式。作为该项目的一部分，将首次计算出海洋的完整三维原始方程模型的罗斯比盆地模态。因此，拟议的工作将推动如何使用海洋环流模型来理解气候系统的前沿。第二项任务将是尝试在现有数据集的组合中检测盆地模式，包括观测数据、数据约束模型集成和无约束模型集成。一种新的投影技术将用于检测噪声数据中的模态结构。第三个任务是通过研究斜压盆地模态对热带（海洋与大气之间的强耦合区域）表面热平衡、海表温度和温跃层深度的影响，验证盆地模态在PDV中发挥重要作用的假设，从而确定太平洋盆地模态是否在年代际尺度上调节了热带海气相互作用和ENSO。智力优势：该项目旨在将盆地模式的概念提升到地球物理流体动力学的基础之上，并将其与年代际气候变化的相关性进行测试。一种新的投影技术将被用于（并进一步发展）检测噪声数据中的动态一致模态结构。此外，先进的数值分析技术将应用于迄今为止最先进和最现实的海洋模型，从而推动计算分析的极限。更广泛的影响：该项目将通过明确识别低频罗斯比波盆地模态的作用，提高太平洋年代际变化的可预测性。通过提高我们对太平洋低频变化的理解，这个项目有可能大大提高预测气候和更好地管理渔业的能力。研究者致力于将他们的研究活动融入到教学和教育推广中。振荡周期超过十年的海盆尺度的波浪最适合捕捉公众的想象力，这些公众对海浪的认识很可能仅限于海浪撞击海滩的高频现象。在加州大学欧文分校（UCI）， Primeau博士将继续为UCI CAMP（促进少数民族学生参与科学）和nsf赞助的UCI FOCUS！（教师外展合作联合科学家，学生和学校）项目通过培训来自少数民族，高需求学区的小学教师。加州大学欧文分校的一名研究生和新墨西哥财团的一名博士后将接受海洋建模、高级数值分析、数据分析和统计方法方面的培训。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This project will investigate the hypothesis that Rossby basin modes play a significant role in Pacific Decadal Variability (PDV). Baroclinic Rossby basin modes are natural oscillations of the ocean with very large spatial scales and periods of up to a decade or more, making them of clear interest for understanding climate variability. The proposed work will consist of three main tasks. The first task will be to systematically determine the periods, decay-rates and spatial patterns of basin modes in the presence of the combined effects of (i) basin geometry and bottom topography, (ii) background circulation and stratification, and (iii) Rossby wave instability. As part of this project the Rossby basin modes of a full three-dimensional primitive equation model of the ocean will be computed for the first time. The proposed work will thus push the frontier of how ocean general circulation models are used to understand the climate system. The second task will be to try to detect basin modes in a combination of available data sets including observations, data-constrained model integrations, and unconstrained model integrations. A novel projection technique will be used to detect modal structures in noisy data. The third task will be to test the hypothesis that basin modes play a significant role in PDV by studying the imprint of baroclinic basin modes on the surface heat budget, sea surface temperature and thermocline depth in the tropics , a place of strong coupling between the ocean and the atmosphere, and so determine if the Pacific basin modes modulate the tropical air-sea interaction and ENSO at decadal time scales. Intellectual Merit: The project aims to elevate the concept of basin modes above its roots in Geophysical Fluid Dynamics, and to bring its relevance for decadal climate variability to the test. A novel projection technique will be used (and further developed) to detect dynamically-consistent modal structures in noisy data. In addition, advanced numerical analysis techniques will be applied to the most advanced and realistic ocean models to date, hence pushing the limits of computational analysis.Broader Impacts: The project will enhance the predictability of Pacific Decadal Variability by unequivocally identifying the role of low-frequency Rossby wave basin modes. By improving our understanding of low-frequency variability in the Pacific ocean this project has the potential of greatly enhancing the ability to predict climate and to better manage fisheries. The investigators are committed to integrating their research activities into teaching and educational outreach. Basin-scale waves with oscillation periods of more than a decade are ideally suited to capture the imagination of a public whose acquaintance with ocean waves is likely to be limited to the high-frequency phenomenon of the surf crashing on the beach. At the University of California, Irvine (UCI), Dr. Primeau will continue to contribute to UCI CAMP (promoting minority-student participation in science), and to the NSF-sponsored UCI FOCUS! (Faculty Outreach Collaborations Uniting Scientists, Students, and Schools) program by training elementary-school teachers from minority, high-need school districts. A graduate student at UC Irvine and a post-doc at the New Mexico Consortium will receive training in ocean modeling, advanced numerical analysis, data analysis and statistical methods.