Secondary Circulations on the Potential Vorticity Staircase: A Theory of Atmospheric Transport

这个项目的目标是研究两种基本的和不同类型的大气环流之间的相互作用：主要环流，由纬向的、东西方向的射流以及它们嵌入的罗斯比波和罗斯比波临界层组成；还有缓慢但持续的次级环流，它在很大程度上是由与初级环流的喷流和波相关的涡流混合驱动的，它控制着整个大气中的长期经向输送。虽然初级环流驱动次级环流，但次级环流也通过动量和辐射活性化学物质（特别是二氧化碳、水蒸气和臭氧）的输送来改变初级环流。这项工作广泛地建立在先前nsf支持的关于“潜在涡度阶梯”和大气纬向喷流性质的研究之上。一个关键主题将涉及审议不均匀涡旋混合对高度和纬度上次级环流分布的影响；其次，化学示踪剂和位涡度梯度的陡增是由次级环流的不同垂直运动引起的。对非平凡垂直结构的重要性和旋涡驱动的次级环流在位势涡度阶梯中的作用的理论研究将通过应用于平流层-对流层和热带-极地动力耦合以及化学示踪剂在整个大气中的输送等专题问题来补充。

The goal of this project is to examine interactions between two fundamental and distinct types of atmospheric circulation: primary circulations, consisting of zonal, east-west directed jets together with their embedded Rossby waves and Rossby-wave critical layers; and the slower but persistent secondary circulations, which are driven to a large extent by the eddy mixing associated with the jets and waves of the primary circulations, and which control long-term meridional transport throughout the atmosphere. Although primary circulations drive secondary ones, the latter also modify the former though the transport both of momentum and of radiatively active chemical species, notably carbon dioxide, water vapor, and ozone. The work builds extensively on previous NSF-supported research on the "potential vorticity staircase" and the nature of atmospheric zonal jets. A key theme will involve a consideration of the influence of inhomogeneous eddy mixing on the distribution of secondary circulations in height and latitude; and, in turn, the steepening of chemical tracer and potential vorticity gradients by the differential vertical motions of the secondary circulations. Theoretical investigations into the importance of non-trivial vertical structure and the role of eddy-driven secondary circulations in the potential vorticity staircase will be complemented by applications to topical issues in stratosphere-troposphere and tropical-polar dynamical coupling and the transport of chemical tracers throughout the atmosphere.