Development and analysis of prognostic equations for Mesoscale kinetic energy and Mesoscale (subgrid scale) fluxes for large-scale atmospheric models

Journal Article · Mon Nov 15 04:00:00 EST 1993 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1993)050<3751:DAAOPE>2.0.CO;2· OSTI ID:5178920

Avissar, R; Chen, Fei ^[1]

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1. Rutgers Univ., New Brunswick, NJ (United States)

Mesoscale circulations generated by landscape discontinuities are likely to have a significant impact on the hydrologic cycle, the climate, and the weather. However, these processes are not represented in large-scale atmospheric models, which have an inappropriate grid-scale resolution. By assuming atmospheric variables can be separated into large scale, mesoscale, and turbulent scale, a set of prognostic equations applicable in large-scale atmospheric models for momentum, temperature, moisture, and any other gaseous or aerosol material, which includes both mesoscale and turbulent fluxes is developed. Prognostic equations are also developed for these mesoscale fluxes, which indicate a closure problem and require a parameterization. The mean mesoscale kinetic energy (MKE) per unit of mass is used, defined as E = 0.5[l angle]u[prime][sub i[sup 2]][r angle], where u[prime][sub i] represents the Cartesian components of a mesoscale circulation (the angle bracket symbol is the grid-scale, horizontal averaging operator in the large-scale model, and a tilde indicates a corresponding large-scale mean value). A prognostic equation is developed for E, and analysis of the different terms of this equation indicates that mesoscale vertical heat flux, the mesoscale pressure correlation, and the interaction between turbulence and mesoscale vertical heat flux, the mesoscale pressure correlation, and the interaction between turbulence and mesoscale perturbations are major terms that affect the time tendency of E. A mesoscale atmospheric model is used to investigate the relationship between MKE, landscape discontinuities, and mesoscale sensible and latent heat fluxes in the atmosphere. MKE is compared with turbulence kinetic energy to illustrate the importance of mesoscale processes as compared to turbulent processes. 38 refs., 52 figs., 2 tabs.

• OSTI ID: 5178920
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 50:2; ISSN JAHSAK; ISSN 0022-4928
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC CIRCULATION
EQUATIONS
FORECASTING
GENERAL CIRCULATION MODELS
MATHEMATICAL MODELS
METEOROLOGY
PREDICTION EQUATIONS