Gravity Wave Dynamics in a Mesospheric Inversion Layer: 1. Reflection, Trapping, and Instability Dynamics

Autor: Ling Wang, Thomas S. Lund, Brian Laughman, David C. Fritts, Richard L. Collins
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Atmospheric Science
010504 meteorology & atmospheric sciences
Theoretical Modeling
gravity wave instabilities
Atmospheric Composition and Structure
Acoustic‐gravity Waves
01 natural sciences
Instability
Physics::Geophysics
gravity wave dynamics
0103 physical sciences
Earth and Planetary Sciences (miscellaneous)
Gravity wave
010303 astronomy & astrophysics
Middle Atmosphere: Energy Deposition
Middle Atmosphere: Constituent Transport and Chemistry
Research Articles
0105 earth and related environmental sciences
Physics
Turbulence
Climate and Dynamics
Longitudinal static stability
Geophysics
Physical Modeling
mesospheric inversion layers
Computational physics
Wavelength
gravity wave reflection and transmission
Amplitude
13. Climate action
Space and Planetary Science
Middle Atmosphere Dynamics
Mesopause
Atmospheric Processes
Tropopause
Mesospheric Dynamics
Natural Hazards
Research Article
Zdroj: Journal of Geophysical Research. Atmospheres
ISSN: 2169-8996
2169-897X
Popis: An anelastic numerical model is employed to explore the dynamics of gravity waves (GWs) encountering a mesosphere inversion layer (MIL) having a moderate static stability enhancement and a layer of weaker static stability above. Instabilities occur within the MIL when the GW amplitude approaches that required for GW breaking due to compression of the vertical wavelength accompanying the increasing static stability. Thus, MILs can cause large‐amplitude GWs to yield instabilities and turbulence below the altitude where they would otherwise arise. Smaller‐amplitude GWs encountering a MIL do not lead to instability and turbulence but do exhibit partial reflection and transmission, and the transmission is a smaller fraction of the incident GW when instabilities and turbulence arise within the MIL. Additionally, greater GW transmission occurs for weaker MILs and for GWs having larger vertical wavelengths relative to the MIL depth and for lower GW intrinsic frequencies. These results imply similar dynamics for inversions due to other sources, including the tropopause inversion layer, the high stability capping the polar summer mesopause, and lower frequency GWs or tides having sufficient amplitudes to yield significant variations in stability at large and small vertical scales. MILs also imply much stronger reflections and less coherent GW propagation in environments having significant fine structure in the stability and velocity fields than in environments that are smoothly varying.
Key Points Gravity waves exhibit complex dynamics in mesospheric inversion layersResponses include trapping, suppressed transmission, reflection, and enhanced shears, instabilities, and dissipationMIL penetration is enhanced for larger vertical wavelengths and lower intrinsic frequencies; larger GW amplitudes enable instabilities
Databáze: OpenAIRE
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