CEDAR Postdoc: Numerical Modeling of Mesospheric Bores, Nonlinear Ducted Waves, and Interpretation of Observations in the Middle Atmosphere

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的，该项目侧重于对中间层钻孔的模拟研究。这些波特征出现在中上层和热层下部，是一个水平范围很大(约500公里)的尖锐波阵面，随后是一系列波峰。1993年首次观测到中间层小孔。自那以后，有许多额外的观察结果，但对细节的了解有限。该项目将定量评估中间层钻孔的动态和特征，包括支持它们的环境、产生它们的作用力以及它们对大气的影响。这项工作有两个主要组成部分：(1)扩展目前已经开发的数值模式，以涵盖中间层和较低热层的典型的更复杂的强迫和环境；(2)模拟观测到的气辉数据，同时进行激光雷达和雷达测量，以描述热环境和风环境。对于任务1，建议的模型扩展将模拟钻孔的更真实的背景条件以及各种类型的钻孔结构对这些条件的响应。第二项任务将使用气辉、雷达和激光雷达观测来提供有关大气背景热结构和钻孔如何传播的信息。数值研究将提高对钻孔动力学的定量理解，并确定如何扩展或修改现有理论以应用于现实环境。对观测的应用还将定义观测如何最好地量化钻孔动力学以及相关的导管现象。该项目的更广泛影响涉及更好地理解和量化中间层和较低热层中的能量和动量输送和沉积，这对平均气流和全球环流模型产生了影响。更好地理解中间层孔的非线性动力学也与低层大气和各种工程应用中的其他动力学相似现象有关。该项目将支持一位新的研究人员在完成博士学位后的第一次研究工作。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)This project focuses on modeling studies of mesospheric bores. These wave features occur in the upper mesosphere and lower thermosphere and are identified as a sharp wave front with a large horizontal extent (on the order of 500 km) followed by a train of wave crests. Mesospheric bores were first observed in 1993. Since then, there have been many additional observations but limited detailed understanding. This project will quantitatively assess the dynamics and characteristics of mesospheric bores, including the environments that support them, the forcings that give rise to them, and their impacts on the atmosphere. The effort has two main components: (1) extend a current numerical model already developed to encompass more complicated forcings and environments typical of the mesosphere and lower thermosphere; (2) model observed airglow data for which concurrent lidar and radar measurements describe the thermal and wind environments. For task 1, the proposed model extensions will simulate more realistic background conditions for the bores along with the responses of various types of bore structures to these conditions. The second task will use airglow, radar, and lidar observations to provide information on the background thermal structure of the atmosphere and on how bores propagate through it. The numerical studies will improve quantitative understanding of bore dynamics and determine how the existing theories might be expanded or amended to apply in realistic environments. Applications to observations will also define how observations can best quantify the bore dynamics as well as related ducting phenomena. The broader impacts of the project concern the implications for better understanding and quantification of energy and momentum transport and deposition in the mesosphere and lower thermosphere, which impacts the mean flow and global circulation models. An improved understanding of the nonlinear dynamics of mesospheric bores is also relevant to other dynamically similar phenomena, both in the lower atmosphere and in various engineering applications. The project will support a new researcher in his first research effort after completion of the Ph.D.