Aspects of the Dynamics of the Coupled Tropsphere-Stratosphere System

对流层顶区分隔对流层和平流层，对一系列大气过程起着重要作用。该区域包括最大风速带（喷射流），它充当大尺度大气扰动（罗斯比波）的波导，并在一定程度上控制着中纬度天气系统的发展。它还在次季节和季节时间尺度上将平流层的动力演变与地球表面附近的环流耦合起来。不同的对流层和平流层源区的化学物质通过对流层顶偶有交换。本项目的目的是研究对流层顶波导附近大尺度波耦合的动力学，这种波耦合如何受到背景大气热结构的影响，以及它如何改变对流层和平流层之间化学成分的交换。将使用不同的方法，包括理论、观测数据分析和数值模拟。该项目的结果将促进我们对对流层顶区域气候和天气相关过程的理解，包括对流层和平流层之间双向耦合背后的过程。特别是，该项目将使人们更好地了解是什么驱动了平流层的行星尺度环流变化，以及这种环流变化如何影响地球表面附近的天气。该项目将进一步提高我们对对流层顶附近的背景大气热结构如何影响对流层和平流层之间交换过程的理解。对对流层顶区域的进一步了解有望最终提高天气和气候模式的保真度，并带来相应的社会效益。该项目将为一名研究生和一名博士后提供培训、教学和研究经验，帮助他们为继续从事科学和/或教育事业做好准备。该项目PI将继续其以往NSF支持的外展活动，向初高中学生讲述大气科学的重大发现。

The tropopause region separating the troposphere and the stratosphere plays an important role for a range of atmospheric processes. This region includes the bands of maximum wind speed (the jet-streams), which act as a waveguide for large-scale atmospheric disturbances (Rossby waves) and govern in part the development of mid-latitude weather systems. It also couples the dynamical evolution of the stratosphere to the circulation near the Earth's surface on sub-seasonal and seasonal time scales. Chemical species of distinct tropospheric and stratospheric source regions are sporadically exchanged through the tropopause. The goal of this project is to study the dynamics of large-scale wave coupling near the tropopause waveguide, how this wave coupling is influenced by the background atmospheric thermal structure, and how it modifies the exchange of chemical constituents between the troposphere and the stratosphere. Different approaches will be used, including theory, observational data analysis, and numerical modeling.The results from this project will advance our understanding of climate- and weather-relevant processes in the tropopause region, including the processes behind the two-way coupling between the troposphere and stratosphere. In particular, the project will lead to a better understanding of what drives planetary scale circulation variability in the stratosphere and how this circulation variability impacts weather near the Earth's surface. The project will furthermore improve our understanding of how the background atmospheric thermal structure near the tropopause influences exchange processes between the troposphere and the stratosphere. An improved understanding of the tropopause region is expected to ultimately lead to improved fidelity of models for weather and climate with corresponding societal benefits. The project will provide training as well as teaching and research experience for a graduate student and a postdoctoral fellow, which will help prepare them for continued careers in science and/or education. The project PI will continue his outreach activities from past NSF support, related to conveying stories of great discoveries in atmospheric science to middle and high school students.