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

合作研究：CEDAR——南半球准两天波的生命周期

• 批准号: 1552176
• 负责人: David Fritts
• 金额: $ 15.99万
• 依托单位: GLOBAL ATMOSPHERIC TECHNOLOGIES AND SCIENCES, INC.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1552176&HistoricalAwards=false
• 关键词: Collaborative; Research; CEDAR; Life; Cycle

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 energy 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 with longitude 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.

大气区域（CEDAR）计划的耦合，能量和动力学是一个基于广泛的，社区引导的高中大气研究计划，旨在理解从大气层通过大气的离子上层向上向上大气的大气区域的行为。该程序的主要主题之一是测量大气波从下部大气向中层和较低热层的转移，这与较低的电离层重叠。与此波耦合相关的重要动力学现象称为准两天波（QTDW），这是中间大气中的大规模波结构，在南半球区域内尤其明显，在空间范围内尤其明显。该结构的寿命在一到两周之间变化，而尚不清楚的快速增长，进化和衰减曲线。该奖项的研究将利用来自NASA卫星的同时数据以高时间分辨率以这种结构的经度遵循空间进展。数据库的10年范围将允许该现象每年与太阳最大和太阳最小值的两个时期进行对抗。 这项研究将通过应用理论原始方程模型的应用来确定什么可能是产生此波结构的主要激发源。将调查两名可能的候选人。一种（斜压不稳定性）是通过平流层喷射流的极端边缘启用的动力不稳定性机制的发展。另一个（惯性不稳定）是由于科里奥利力的大小非常弱，在地理赤道附近通电的不稳定性过程。 该奖项的更广泛影响是我们对基本MLT动态的整体理解的提高。研究生将获得半场支持。拟议的活动将直接解决有关大气高度区域之间耦合以及QTDW波现象学与区域平均循环之间可能的能量反馈的问题。 QTDW结构将从一代区域整体研究到110公里。将检查整个层面和介质边界的动量和能量交换。这项研究将涵盖2002年至今的十年观察结果，这将允许研究对比年，例如平流层变暖的可能影响。