Investigation of Nonlinear Gravity Waves in the Earth's Atmosphere

将在一系列研究中使用一个高分辨率、时间相关的非线性二维重力波模型，以了解重力波的强迫、传播、破裂的动力学及其在修正大气层中更大尺度运动中的作用。这些研究将使用理想化流动情况的模拟来阐明基本的动力学过程，同时使用更现实的模拟来了解重力波在大气中的影响的大小和分布。我们的数值研究将以NMC全球风温分析和全球地形数据确定的山波产生和传播估计为指导。这些调查还将涉及使用来自平地雷达系统的观测数据以及美国宇航局的飞机实验来验证模型结果。这个项目的最终目标是估计从对流层逃逸的重力波通量作为平均气流条件和地形的函数，并开发用于大气环流模式的重力波应力和传输的参数化方案。这项调查的结果还可能有助于澄清小尺度(小于100公里)变化对平流层中气溶胶和PSC的输送和微物理的影响。拟议研究的第二个目标将是通过一系列数值实验来研究大幅度大气孤立波的动力学。PI的实验将以孤立波特性的理论分析和从平地雷达对大气孤立波的直接观测为指导。PI的研究将特别关注检查背景大气流动的孤立波结构的敏感性。

A high resolution, time dependent, nonlinear, two- dimensional gravity wave model will be used in a series of investigations to understand the dynamics of gravity wave forcing, propagation, breakdown, and their role in modifying larger scale motions in the atmospehre. These studies will use simulations of idealized flow situations to clarify basic dynamical processes in parallel with more realistic simulations to understand the magnitude and distribution of gravity wave effects in the atmosphere. Our numerical studies will be guided by estimates of mountain wave generation and propagation determined from NMC global wind and temperature analyses and global topographic data. These investigations will also involve use of observational data from the Flatland radar system as well as NASA's aircraft experiments to verify model results. The ultimate objectives of this project are to estimate the amount of gravity wave flux escaping from the troposphere as a function of mean flow conditions and topography and to develop parametrization schemes for gravity wave stress and transport to be used in general circulation models. Results from this investigation may also help to clarify the effect of small-scale (less than 100 km) variability on the transport and microphysics of aerosols and PSC's in the stratosphere. A second objective of the proposed research will be to investigate the dynamics of large amplitude atmospheric solitary waves with a series of numerical experiments. The PI's experiments will be guided by both theoretical analyses of solitary wave properties and by direct observations of atmospheric solitary waves from the Flatland Radar. The PI's studies will be especially concerned with examining the sensitivity of solitary wave structure of the background atmospheric flow.