Theoretical and Numerical Investigations of the Earth's Midlatitude Tropopause

该项目将研究在温带纬度维持对流层顶高度及其渗透性的动力机制。了解中纬度对流层顶的形成、维持和运动学仍然是动力气象学中的一个核心和具有挑战性的问题。最近对其动态渗透性的兴趣源于它对包括臭氧和水蒸气在内的化学成分在对流层和平流层之间的输送的相当大的影响。中村博士(芝加哥大学)将从理论和数值两方面研究这个问题。用准地转和环流模式进行的数值计算将把对流扩散方程的理论分析扩展到更实际的情形，包括涡势涡通量穿透对流层顶的情形。该项目将推动从理论上理解对流层和平流层之间的动力相互作用，并应分别估计平流层到对流层以及对流层到平流层的质量转移，这将改进对跨对流层顶微量气体和物质输送的模拟和预测。

The project will investigate the dynamical mechanisms maintaining tropopause height and its permeability in the extratropical latitudes. Understanding the formation, maintenance, and kinematics of the midlatitude tropopause remains a core, challenging problem in dynamic meteorology. Recent interest in its dynamic permeability stems from its considerable impact on transport of chemical constituents, including ozone and water vapor, between the troposphere and stratosphere. Dr. Nakamura (U of Chicago) will investigate the problem both theoretically and numerically. Numerical calculations with quasi-geostrophic and general circulation models will expand the theoretical analysis of the advection-diffusion equation to more realistic scenarios, including one involving penetration of the tropopause by the eddy potential vorticity fluxes. The project will advance theoretical understanding of the dynamical interaction of the troposphere and stratosphere, and should provide separate estimates of the stratosphere-to-troposphere, and troposphere-to-stratosphere mass transfers, which will improve modeling and prediction of cross-tropopause transports of trace gases and substances.