DOI: 10.1002/jgrd.50514
论文题名: Instability structures during periods of large Richardson number (Ri > 1 4): Evidence of parametric instability
作者: Walterscheid R.L. ; Gelinas L.J. ; Hecht J.H. ; Liu A.Z.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 13 起始页码: 6929
结束页码: 6939
语种: 英语
英文关键词: Floquet theory
; gravity waves
; parametric instability
Scopus关键词: Differential equations
; Gravity waves
; Shear flow
; Convective instabilities
; Floquet systems
; Floquet theory
; Parametric instabilities
; Richardson number
; Ripple structure
; Small-scale instability
; Two-dimensional instability
; Stability
; fractionation
; gravity wave
; instability
; mesosphere
; parameterization
; Richardson number
; survey
英文摘要: The commonly used criteria for shear and convective instabilities were developed for steady horizontally uniform background flows. However, the formalism that rigorously addresses the instability of waves on a basic state modulated by a primary wave is Floquet theory in which the basic state includes a wave. A Floquet system supports parametric instabilities when conventional Richardson number (Ri) criteria indicate that the system is stable. In a study of small-scale instability structures during the Maui MALT campaign, Hecht et al. (2005) noted that there were occurrences of ripple (instability) structure when the conventional criteria indicated stable conditions. We have followed up this work with a detailed survey of the occurrence of ripple structure over Maui during periods that were both stable and unstable according to conventional criteria. Values of Ri were calculated from lidar data. We have found frequent occurrence of ripple structure when Ri > 14. We have focused on a period when there are clear indications of waves and ripple structure exhibiting two-dimensional instability structure when Ri ~ 1 or greater. These results are analyzed in terms of Floquet theory and interpreted as parametric instabilities occurring for modest primary wave amplitudes. Key Points Large Richardson number instabilities in upper mesophere Evidence of upper mesosphere parametric instability Significant fraction of ripple structure may be parametric instabilities ©2013. American Geophysical Union. All Rights Reserved. 资助项目: NNX08AM13G
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63561
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Space Science Applications Laboratory, Aerospace Corporation, Los Angeles, CA, United States; Department of Physical Sciences, Embry-Riddle Aeronautical University, Daytona Beach, FL, United States
Recommended Citation:
Walterscheid R.L.,Gelinas L.J.,Hecht J.H.,et al. Instability structures during periods of large Richardson number (Ri > 1 4): Evidence of parametric instability[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(13)