Collaborative Research: Towards an Understanding of the Role of the Atlantic Theremohaline and Wind Driven Circuluation in Tropical Atlantic Variability (TAV)

最近的耦合气候模式模拟表明，大西洋温盐环流的变化可以导致热带大西洋耦合气候系统的实质性响应，这反过来又会对全球气候产生影响。如果这被证明是正确的，这些模拟结果可能对我们理解海洋在全球气候变化中的作用产生巨大影响。因此，我们必须全面了解将高纬度地区的变化与热带地区的变化联系起来的动力过程。该项目的重点是海洋联系。特别是，研究人员将探索大西洋经向翻转单元（MOC）的变化如何影响亚热带单元（STC）的路径，以及STC的这些变化如何影响海表面温度（SST），以及最终这些SST变化如何影响热带大西洋的耦合气候变率。调查将通过一系列耦合气候模式结合观测分析进行。一个大气模式耦合到一个2.5层简化重力海洋模式，也许是最简单的，但最有效的耦合模式适合于调查MOC/STC的相互作用及其对耦合气候变率的影响，将被用来进行广泛的面向过程的实验，通过改变强加的MOC的强度，揭示MOC对热带大西洋变率（TAV）的影响。然后，一个大气环流模式耦合到一个区域高分辨率海洋环流模式，能够解决热带大西洋环流的中尺度特征，将被迫通过其北方和南方的开放边界，让一个更完整的看看MOC/STC耦合反馈的效果。最后，将分析用于IPCC评估的综合全球耦合气候模式的输出，并与其他两个模式试验结合使用，以进一步了解大西洋MOC变化对全球气候的影响。这项研究的预期成果将对了解大西洋气候变率和全球气候变化中的基本海洋环流物理学作出重要贡献。气候变化通过假设检验和对耦合模型实验的系统检查，预计这项研究将产生一个关于大西洋环流不同组成部分之间联系的更精确的理论。在这项研究中开发的模拟工具将是有价值的未来的气候研究。更广泛的影响：拟议的研究解决了与气候变化科学的辩论和讨论有关的问题。拟议的研究将增进我们对热带大西洋地区长期气候多变性的了解，这对该区域各国具有重要的社会和经济影响。这项研究的结果将有助于教育公众海洋在全球气候变化中的重要性。该项目还将通过直接让研究生和博士后研究人员与教师一起参与研究工作，帮助培养下一代物理海洋学家和气候科学家。该项目的一些研究成果将被纳入TAMU的研究生课程。

ABSTRACTOCE-0623364Recent coupled climate model simulations show that changes in thermohaline circulation in the Atlantic Ocean can lead to a substantial response in the tropical Atlantic coupled climate system, which in turn can have an impact on global climate. If this proves correct, these modeling results can have tremendous implications on our understanding of the role of the ocean in global climate change. For this reason, it is critically important for us to gain a comprehensive understanding of the dynamical processes that link the changes in high latitudes to those in the tropics. The focus of this project is on the oceanic linkage. In particular, the investigators will explore how changes in the Atlantic Meridional Overturning Cell (MOC) can affect the pathways of the Sub-Tropical Cells (STCs), and how these changes in the STCs can affect the Sea Surface Temperatures (SSTs), and finally how these SST changes can affect the coupled climate variability in the tropical Atlantic. The investigation will be conducted via a hierarchy of coupled climate models in conjunction with observational analysis. An atmospheric model coupled to a 2.5-layer reduced-gravity-ocean model, perhaps the simplest and yet most efficient coupled model suited to investigate MOC/STC interaction and its effect on coupled climate variability, will be used to conduct extensive process-oriented experiments by varying the strength of the imposed MOC to shed light on the effect of the MOC on the Tropical Atlantic Variability (TAV). Then , an atmospheric circulation model coupled to a regional high resolution ocean circulation model capable of resolving mesoscale features in the tropical Atlantic circulation will be forced through its northern and southern open boundaries to allow a more complete look at the effect of the MOC/STCs on coupled feedback. Finally, the output of a comprehensive global coupled climate model used for IPCC assessment will be analyzed and used in conjunction with the other two model experiments to gain further understanding of the impact of Atlantic MOC change on global climate.INTELLECTUAL MERIT: The anticipated outcome of this research will make an important contribution to the understanding of the fundamental ocean circulation physics in Atlantic climate variability and global climate change. A more refined theory of the connection between the different components of the Atlantic ocean circulation is expected to emerge from this study through hypothesis testing and systematic examination of the coupled model experiments. The modeling tools developed in this study will be valuable for future climate studies. BROADER IMPACT: The proposed research addresses the issues pertinent to debates and discussions in climate change sciences. The proposed research will enhance our understanding of long-term climate variability in the tropical Atlantic sector, which has important social and economic impacts on countries in the region. The findings from this study will help educate the general public about the importance of the oceans in global climate change. The project will also help train the next generation of physical oceanographers and climate scientists by directly involving graduate students and postdoctoral researchers in research endeavors with faculty. Some of research results from this project will be integrated into the graduate courses at TAMU.