DOI: 10.1029/2017JD027970
Scopus记录号: 2-s2.0-85052047257
论文题名: The Excitation of Secondary Gravity Waves From Local Body Forces: Theory and Observation
作者: Vadas S.L. ; Zhao J. ; Chu X. ; Becker E.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 17 起始页码: 9296
结束页码: 9325
语种: 英语
英文关键词: Antarctica
; body forces
; lidar measurements
; secondary gravity waves
英文摘要: We examine the characteristics of secondary gravity waves (GWs) excited by a localized (in space) and intermittent (in time) body force in the atmosphere. This force is a horizontal acceleration of the background flow created when primary GWs dissipate and deposit their momentum on spatial and temporal scales of the wave packet. A broad spectrum of secondary GWs is excited with horizontal scales much larger than that of the primary GW. The polarization relations cause the temperature spectrum of the secondary GWs generally to peak at larger intrinsic periods τIr and horizontal wavelengths λH than the vertical velocity spectrum. We find that the one-dimensional spectra (with regard to frequency or wave number) follow lognormal distributions. We show that secondary GWs can be identified by a horizontally displaced observer as “fishbone” or “>” structures in z − t plots whereby the positive and negative GW phase lines meet at the “knee,” zknee, which is the altitude of the force center. We present two wintertime cases of lidar temperature measurements at McMurdo, Antarctica (166.69°E, 77.84°S) whereby fishbone structures are seen with zknee=43 and 52 km. We determine the GW parameters and density-weighted amplitudes for each. We show that these parameters are similar below and above zknee. We verify that the GWs with upward (downward) phase progression are downward (upward) propagating via use of model background winds. We conclude that these GWs are likely secondary GWs having ground-based periods τr=6–10 hr and vertical wavelengths λz=6–14 km, and that they likely propagate primarily southward. ©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/113175
Appears in Collections: 气候减缓与适应
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作者单位: Northwest Research Associates, Boulder, CO, United States; Cooperative Institute for Research in Environmental Sciences and Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States; Leibniz Institute of Atmospheric Physics, Kühlungsborn, Germany
Recommended Citation:
Vadas S.L.,Zhao J.,Chu X.,et al. The Excitation of Secondary Gravity Waves From Local Body Forces: Theory and Observation[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(17)