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Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999

FROM VOLUME 8, NUMBER 4, APRIL 1995

PROFESSIONAL PUBLICATIONS...
OF GENERAL INTEREST: CLOUDS AND CLIMATE

Item #d95apr24

Three related papers in Science, 267(5197), Jan. 27, 1995:

"Darker Clouds Promise Brighter Future for Climate Models," R.A. Kerr, 454. Comments on the implications of the next two papers in this issue, and the following one by Pilewskie and Valero, all of which report measurements showing that clouds absorb more solar radiation than is represented in global climate models.

"Absorption of Solar Radiation by Clouds: Observations Versus Models," R.D. Cess (Marine Sci. Res. Ctr., State Univ. N.Y., Stony Brook NY 11794), M.H. Zhang et al., 496-499. Collocated satellite and surface measurements of solar radiation at five geographically diverse locations show significantly more solar absorption by clouds than predicted by theoretical models. The effect is spatially uniform, suggesting that tropospheric aerosols (pollutants) are not the cause. The physical cause remains unknown, but the result substantially alters our understanding of the atmosphere's energy budget.

"Warm Pool Heat Budget and Shortwave Cloud Forcing: A Missing Physics?" V. Ramanathan (Ctr. Clouds, Chem. & Clim., Scripps Inst. Oceanog., La Jolla CA 92093), B. Subasilar et al., 499-503. Uses estimates of the heat export from the mixed layer of the Pacific warm pool to determine the effect of clouds on the net solar radiation at the sea surface. Clouds there seem to trap a large amount of solar radiation in the cloudy atmosphere, an inference at variance with most model results, and one which has many climatic implications.

Item #d95apr25

"Direct Observations of Excess Solar Absorption by Clouds," P. Pilewskie (NASA-Ames, Moffett Field CA 94035), F.P.J. Valero, Science, 267(5204), 1626-1629, Mar. 17, 1995.

Aircraft measurements of solar flux in the cloudy tropical atmosphere reveal that solar absorption by clouds is anomalously large compared to theoretical estimates, implying that the interaction between clouds and solar radiation is poorly understood.