A Parameterization for the Shortwave Transmissivity of Stratiform Water Clouds Based on Empirical Data and Radiative Transfer Theory

Autor: L. S. Fedor, Howard P. Hanson, V. E. Derr, Robert S. Stone
Rok vydání: 1990
Předmět:
Zdroj: Journal of the Atmospheric Sciences. 47:2774-2783
ISSN: 1520-0469
0022-4928
DOI: 10.1175/1520-0469(1990)047<2774:apftst>2.0.co;2
Popis: Surface measurements of solar flux and total integrated liquid-water content, radiosonde data, and infrared satellite images are analyzed in conjunction with radiative transfer calculations to derive an empirical parameterization for the shortwave transmissivity of continental stratiform water clouds. The data were collected near Denver, Colorado, over a period of six years. A multiple reflection radiative transfer model is employed to estimate stratus cloud transmissivity in terms of the measurable liquid-water path (LWP). A nonlinear fit of estimated transmissivities to the corresponding observations of LWP yields close agreement with a previous, more complicated parameterization. The derived expression for cloud transmissivity is used to predict mean daily surface fluxes for 61 days during which periods of stratiform clouds were observed over the Denver area. A comparison between predicted and measured fluxes shows agreement to within + or - 4 percent, with best agreement for clouds of moderate optical thickness. Potential sources of error are identified with sensitivity studies.
Databáze: OpenAIRE