Radiative horizontal transport and absorption in stratocumulus clouds

Journal Article · Sat Aug 01 04:00:00 EDT 1998 · Journal of the Atmospheric Sciences

DOI:https://doi.org/10.1175/1520-0469(1998)055<2549:RHTAAI>2.0.CO;2· OSTI ID:638277

Titov, G A ^[1]

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1. Russian Academy of Sciences, Tomsk (Russian Federation)

The equation of radiative energy balance in a homogeneous plane-parallel cloud accounts for the photon transport in the vertical direction only. From this equation, the absorption can be evaluated as a difference between the net radiative fluxes measured on the cloud top and bottom. Real clouds exhibit extreme horizontal variability of their optical and, hence, radiative properties. So the radiative energy balance equation for inhomogeneous clouds includes an extra term to describe the net energy transport in the horizontal directions (radiative horizontal transport). This study investigates the horizontal transport in nonhomogeneous stratocumulus clouds and its influence on the accuracy of absorption estimates. Using a realistic fractal model of marine stratocumulus clouds and Monte Carlo method, it is shown that the magnitude of horizontal transport (1) is comparable with those of albedo, transmittance, and absorptance and (2) depends strongly on the fractal dimension of cloud optical depth. Because of the horizontal transport, there is no unique dependence between optical and radiative properties of given pixel. The neglect of the horizontal transport is a major source of uncertainty in absorption estimates. Two possible ways of improving the inhomogeneous cloud absorption estimates from field measurements are discussed.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• OSTI ID: 638277
• Journal Information: Journal of the Atmospheric Sciences, Journal Name: Journal of the Atmospheric Sciences Journal Issue: 15 Vol. 55; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ABSORPTION
CLIMATES
CLIMATIC CHANGE
CLOUDS
ENERGY TRANSFER
MASS TRANSFER