Gravity Wave Dynamics in a Mesospheric Inversion Layer: 2. Instabilities, Turbulence, Fluxes, and Mixing
Autor: | Brian Laughman, Richard L. Collins, Ling Wang, David C. Fritts, Thomas S. Lund |
---|---|
Rok vydání: | 2018 |
Předmět: |
Physics
Atmospheric Science 010504 meteorology & atmospheric sciences K-epsilon turbulence model Turbulence K-omega turbulence model Mechanics Dissipation 01 natural sciences Instability 010305 fluids & plasmas Geophysics Classical mechanics Amplitude Space and Planetary Science 0103 physical sciences Earth and Planetary Sciences (miscellaneous) Gravity wave Adiabatic process 0105 earth and related environmental sciences |
Zdroj: | Journal of Geophysical Research: Atmospheres. 123:649-670 |
ISSN: | 2169-8996 2169-897X |
Popis: | A companion paper by Fritts et al. [2017a] employed an anelastic numerical model to explore the dynamics of gravity waves (GWs) encountering a mesospheric inversion layer (MIL) having a moderate static stability enhancement and a layer of weaker static stability above. That study revealed that MIL responses, including GW transmission, reflection, and instabilities, are sensitive functions of GW parameters. This paper expands on two of the Fritts et al. [2017a] simulations to examine GW instability dynamics and turbulence in the MIL, forcing of the mean wind and stability environments by GW, instability, and turbulence fluxes, and associated heat and momentum transports. These direct numerical simulations resolve turbulence inertial-range scales and yield the following results: GW breaking and turbulence in the MIL occur below where they would otherwise due to enhancements of GW amplitudes and shears in the MIL, 2D GW and instability heat and momentum fluxes are ~20-30 times larger than 3D instability and turbulence fluxes, mean fields are driven largely by 2D GW and instability dynamics rather than 3D instabilities and turbulence, 2D and 3D heat fluxes in regions of strong turbulence yield small departures from initial T(z) and N2(z) profiles, hence do not yield nearly adiabatic “mixed” layers, and our MIL results are consistent with the relation between the turbulent vertical velocity variance and energy dissipation rate proposed by Weinstock [1981] for the limited intervals evaluated. |
Databáze: | OpenAIRE |
Externí odkaz: |