Tropical Atmosphere/Ocean Variability in the Boreal Summer and Its Relationship with Atlantic Hurricanes

大西洋子午线模式(AMM)是大西洋耦合变率的主要模式，它代表了一种独特的海表面温度和大气场的耦合模式，这种模式通过广泛的外部强迫机制而出现。以前的工作表明，AMM可以为观测到的与热带气旋形成相关的一些区域大气和海洋条件之间的一致性提供动力学解释。这个项目的目的是更好地了解北方夏季AMM变化的原因，重点是了解AMM与热带气旋活动之间的联系。这项研究将利用全球大气环流模式的设计实验、简单耦合模式的动力学分析、观测数据的分析和解释，以及对现有全球耦合模式模拟当前和未来气候的分析。具体地说，这个项目将解决(I)北半球夏季的AMM结构是什么？(Ii)在北方夏季，什么动力过程控制着AMM，以及AMM与影响飓风活动的环境条件之间的关系？(3)什么外部强迫机制会影响北部夏季的热带气旋活动，大西洋十年振荡(AMO)和热带气旋活动之间有什么关系？(4)大西洋十年振荡的可预测性是什么，以及哪些过程影响了这种可预测性？该项目的更广泛影响包括鼓励气候动力学和热带气旋特征学科之间的结合，培训两名研究生和一名博士后研究员，在国内和国际场所更广泛地传播结果，以及公开与AMM和热带气旋活动有关的实时数据。

The Atlantic Meridional Mode (AMM) is the leading mode of coupled variability in the Atlantic, and represents a distinct coupled pattern of sea surface temperature and atmospheric fields that emerges through a broad spectrum of external forcing mechanisms. Previous work has shown that the AMM may provide a dynamical explanation for the observed coherence between a number of regional atmospheric and oceanic conditions that are relevant for tropical cyclone formation. This project aims to better understand the cause of AMM variations during boreal summer, with an emphasis on understanding the link between the AMM and tropical cyclone activity. The research will utilize designed experiments using global general circulation models, dynamical analysis of simple coupled models, analysis and interpretation of observational data, and analysis of existing global coupled model simulations of present and future climate. Specifically, this project will address (i) What is the structure of the AMM during boreal summer? (ii) What dynamical processes control the AMM during boreal summer, and the relationship between the AMM and environmental conditions that influence hurricane activity? (iii) What external forcing mechanisms influence the AMM during boreal summer, and what is the relationship between the Atlantic Multidecadal Oscillation (AMO) and AMM, and (iv) What is the predictability of the AMM, and what processes influence that predictability?Broader impacts of this project include encouraged integration between the disciplines of climate dynamics and tropical cyclone characteristics, training of two graduate students and one post-doctoral researcher, broader dissemination of results in national and international venues, and public availability of real-time data relating to the AMM and to tropical cyclone activity.