Physical processes within the nocturnal stratus-topped boundary layer

Journal Article · Tue Dec 15 04:00:00 EST 1992 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1992)049<2384:PPWTNS>2.0.CO;2· OSTI ID:7065260

Moeng, C H; Shen, S ^[1]; Randall, D A ^[2]

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1. National Center for Atmospheric Research, Boulder, CO (United States)
2. Colorado State Univ., Fort Collins (United States)

Within the stratus-topped boundary layer many physical processes are involved: longwave radiation cooling, entrainment, latent heating, surface heating, solar heating, drizzling, etc. How all processes combine to maintain the turbulence within the stratus-topped boundary layer remains an unsolved problem. The large-eddy simulation technique is used to examine the first four physical processes mentioned. First, the contribution of each physical process to the thermodynamic differences between the updraft and downdraft branches of turbulent circulations is examined through a conditional sampling. Second, these mean thermodynamic differences are shown to express well the vertical distributions of heat and moisture fluxes within stratus-topped boundary layers. These provide a method to validate the process-partitioning technique. (This technique assumes that the net flux profile can be partitioned into different component-flux profiles according to physical processes and that each partitioned component flux is linear in height.) In this paper, the heat and moisture fluxes are process partitioned, and each component flux is found to contribute to the net flux in a way that is consistent with its corresponding process contribution to the mean thermodynamic differences between updrafts and downdrafts. Also, the net flux obtained by summing all component fluxes agrees well with that obtained directly from the large-eddy simulations.

• OSTI ID: 7065260
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 49:24; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC CIRCULATION
BOUNDARY LAYERS
CLIMATE MODELS
CLOUD COVER
COOLING
HEATING
LAYERS
MATHEMATICAL MODELS
MOISTURE
NOCTURNAL VARIATIONS
SIMULATION
SOLAR HEATING
THERMODYNAMICS
TURBULENCE
VARIATIONS