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

GSTDTAP

项目编号	1552255
	Collaborative Research: CEDAR--Life Cycle of the Quasi Two-Day Wave in the Southern Hemisphere
	David Ortland
主持机构	NorthWest Research Associates, Incorporated
项目开始年	2016
	2016-03-15
项目结束日期	2019-02-28
资助机构	US-NSF
项目类别	Continuing grant
项目经费	24346(USD)
国家	美国
语种	英语
英文摘要	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.
来源学科分类	Geosciences - Atmospheric and Geospace Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69223
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	David Ortland.Collaborative Research: CEDAR--Life Cycle of the Quasi Two-Day Wave in the Southern Hemisphere.2016.