Collaborative Research: CEDAR--Life Cycle of the Quasi Two-Day Wave in the Southern Hemisphere

大气区域的耦合、能量学和动力学（CEDAR）计划是一个基础广泛、社区指导的高层大气研究计划，旨在了解从低层大气向上通过电离的高层大气的大气区域的行为。这个项目的一个主要主题是测量从低层大气到中间层和低层热层的大气波活动的转移，这些层与低层电离层重叠。与这种波耦合相关的一个重要动力学现象被称为准两日波（QTDW），这是一种大尺度波结构，在大气中部的风和温度中可见，在南半球地区尤为明显，其空间范围超过数千公里。这种结构的寿命在一到两周之间变化，具有快速的增长、演变和衰减曲线，目前尚不清楚。该合同的研究将利用NASA两颗卫星的同步数据，以高时间分辨率跟踪该结构的空间进展。数据库的10年范围将允许对这一现象进行年与年的相互比较，并对太阳极大期和太阳极小期进行比较。这项研究将通过应用理论原始方程模型来确定产生这种波结构的主要激发源是什么。将调查两名可能的候选人。一种（斜压不稳定）是由平流层喷流的极向边缘激发的动力不稳定机制的发展。另一种（惯性不稳定）是地理赤道附近由于科里奥利力的非常弱而激发的不稳定过程。该奖项更广泛的影响是提高了我们对基本MLT动力学的整体理解。一名研究生将获得半天的资助。提出的活动将直接解决大气高度区域之间的耦合问题，以及QTDW波现象与纬向平均环流之间可能的能量反馈问题。QTDW结构将从产生区域到110 km区域进行整体研究。动量和能量交换跨越平流层顶和中层顶边界将被检查。这项研究将包括从2002年到现在的十年观测，这将允许研究对比年份，例如，平流层变暖的可能影响。

The Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) program, a broad-based, community-guided, upper atmospheric research program, is aimed at understanding the behavior of atmospheric regions from the lower atmosphere upward through the ionized upper layers of the atmosphere. One of the major themes of this program is the measurement of the transfer of atmospheric wave activity from the lower atmosphere into the mesosphere and lower thermosphere, which overlaps the lower ionosphere. An important dynamical phenomenon associated with this wave coupling is called the quasi two-day wave (QTDW), which is a large-scale wave structure seen in the middle atmosphere winds and temperatures that is particularly pronounced within the southern hemisphere region with a spatial extent over many thousands of km. The lifetime of this structure varies between one and two weeks with a rapid growth, evolution, and decay profile that is not understood. The research of this award would utilize simultaneous data from two NASA satellites to follow the spatial progression of this structure with high temporal resolution. The 10 years extent of the database will allow this phenomenon to be intercompared from year to year and for the two periods of solar maximum and solar minimum. This research would determine through the application of a theoretical primitive equation model what might be the predominant excitation source generating this wave structure. Two possible candidates would be investigated. One (baroclinic instability) is the development of a dynamical instability mechanism energized by the poleward edge of the stratospheric jet stream. The other (inertial instability) is an instability process energized near the geographic equator as a result of the very weak magnitude of the Coriolis force. The broader impact of this award is the improvement of our overall understanding of fundamental MLT dynamics. A graduate student would receive half-time support.The proposed activity will directly address questions regarding the coupling between atmospheric height regions, and possible energetics feedbacks between the QTDW wave phenomenology and the zonal mean circulation. The QTDW structure will be holistically investigated from the generation region into the 110 km region. Momentum and energy exchange across the stratopause and mesopause boundaries will be examined. The study will encompass a decade of observations, 2002-present, which will allow study of contrasting years, e.g., the possible influence of stratospheric warmings.