DOI: 10.1029/2017JD027617
Scopus记录号: 2-s2.0-85052830967
论文题名: Localization Effects on the Dissipation of Gravity Wave Packets in the Upper Mesosphere and Lower Thermosphere
作者: Heale C.J. ; Walterscheid R.L. ; Snively J.B.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 17 起始页码: 8915
结束页码: 8935
语种: 英语
英文关键词: dissipation
; gravity waves
; MLT
英文摘要: Gravity waves not subject to breaking or filtering will dissipate due to viscosity and thermal conduction in the thermosphere. However, the evolutions of wave packets, and the altitudes they reach, are highly dependent upon the spectral content. In this paper, a 2-D numerical model is used to investigate the effect of spatial localization (and thus spectral content) of a wave packet on its dissipation, dispersion, and spectral evolution. It is found that most wave packets launched below the thermosphere evolve to smaller central vertical wavelengths as the faster, longer vertical wavelength components reach the dissipative thermosphere and are removed first, leaving the shorter, slower components to become dominant at later times. This effect is greater for more spatially localized packets (spectrally broadband) as rapid dispersion leads to the rapid spreading of the wave over large altitude regions that could be interpreted as different waves (i.e., from different sources) by instruments observing different altitudes. Dispersion can also be accelerated by the refractive effects of the thermospheric temperature gradient. Initially, Gaussian broadband packets can evolve into asymmetric distributions which are not well described by standard assumptions (e.g., Gaussian packets), requiring instead numerical simulation to properly describe them. In the case that the vertical scale is smaller than the scale height, and dissipation acts immediately on the packet (i.e., it is generated in situ in the dissipative thermosphere), then the scale-dependent nature of dissipation removes the shorter wavelengths components first, leading to the spectrum evolving toward larger vertical wavelengths. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113198
Appears in Collections: 气候减缓与适应
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作者单位: Center for Space and Atmospheric Research, Department of Physical Sciences, Embry-Riddle Aeronautical University, Daytona Beach, FL, United States; Space Science Applications Laboratory, The Aerospace Corporation, El Segundo, CA, United States
Recommended Citation:
Heale C.J.,Walterscheid R.L.,Snively J.B.. Localization Effects on the Dissipation of Gravity Wave Packets in the Upper Mesosphere and Lower Thermosphere[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(17)