Last Updated:
February 28, 2007

GCRIO Program Overview

Library 
Our extensive collection of documents.

Privacy Policy

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

FROM VOLUME 7, NUMBER 2, FEBRUARY 1994

PROFESSIONAL PUBLICATIONS...

• CLOUDS, AEROSOLS AND CLIMATE

Item #d94feb28

"Reassessing the Dependence of Cloud Condensation Nucleus [CCN] Concentration on Formation Rate," A.S. Ackerman (Dept. Atmos. Sci., AK-40, Univ. Washington, Seattle WA 98195), O.B. Toon, P.V. Hobbs, Nature, 367(6462), 445-447, Feb. 3, 1994.

Previous work postulated that a bistable CCN concentration regime could be established in marine stratocumulus, implying that a small increase in CCN over the oceans could drastically increase planetary albedo. Improved model calculations presented here do not support this theory, but do indicate that high CCN concentrations can persist in clouds advected to regimes of lower CCN production rate.

Item #d94feb29

"The Potential Role of the Ocean in Regulating Atmospheric CH3Br," J.H. Butler, (CMDL, NOAA, 325 Broadway, Boulder CO 80303), Geophys. Res. Lett., 21(3), 185-188, Feb. 1, 1994.

Uses a simple coupled atmosphere-ocean model to evaluate the oceanic effect and its potential response to changes in anthropogenic emissions of CH3Br. Finds an effective atmospheric lifetime of 1.2 years.

Item #d94feb30

"Potential Effects of Cloud Optical Thickness on Climate Warming," G. Tselioudis (NASA Goddard Inst. Space Studies, 2880 Broadway, New York NY 10025), A.A. Lacis et al., Nature, 366(6456), 670-672, Dec. 16, 1993.

Previous results from the International Satellite Cloud Climatology Project have shown a relationship between low-cloud optical thickness and cloud temperature that implies a positive feedback between clouds and climate. This paper presents calculations for a doubled CO2 climate using a 2-D radiative-convective model, showing a latitudinal gradient in the strength of this feedback that tends to eliminate the high-latitude amplification of greenhouse warming predicted by most climate models.

Item #d94feb31

"Aerosols and Global Warming," O. Preining (Inst. Exper. Phys., Univ. Vienna, Strudlhofgasse 4, 1090 Vienna, Austria), World Resour. Rev., 5(4), 409-413, Dec. 1993.

Uses some simple calculations to demonstrate why aerosols must be included properly in all climate models.

Item #d94feb32

"On the Relationship Between Sulfate and Cloud Droplet Number Concentrations," W.R. Leaitch (Cloud Phys. Res. Div., Atmos. Environ. Serv., 4905 Dufferin St., Downsview ON M3H 5T4, Can.), G.A. Isaac, J. Clim., 7(1), 206-212, Jan. 1994.

Compares observations of cloud droplet and cloud water sulfate concentrations with the theoretical implications of modeling by Kaufman et al. In terms of their prediction of the range of possibilities for future climate, the data favor the possibility of stronger cooling, but the uncertainty in modeling this process is large and poorly constrained by the data.

Item #d94feb33

"Aqueous Greenhouse Species in Clouds, Fogs and Aerosols," N.A. Marley, J.S. Gaffney (Bldg. 203, Argonne Natl. Lab., Argonne IL 60439), M.M. Cunningham, Environ. Sci. Technol., 27(13), 2864-2869, Dec. 1993.

Describes measurements of water-soluble infrared absorbers that can contribute to the long-wave radiation forcing of clouds, fogs and aerosols, including sulfate, nitrate, formate, acetate, oxalate, phenol, p-nitrophenol, ammonium, bicarbonate, formaldehyde, methanol and ethanol. Discusses relative effects on radiative forcing.

Item #d94feb34

"Seasonal, Latitudinal, and Secular Variations in Temperature Trend: Evidence for Influence of Anthropogenic Sulfate," D.E. Hunter (Scripps Inst. Oceanog., La Jolla CA 92093), S.E. Schwartz et al. Geophys. Res. Lett., 20(22), 2455-2458, Nov. 19, 1993.

Finds pronounced summer minima in the rate of temperature increase in the Northern Hemisphere midlatitudes that are consistent with the latitudinal distribution of anthropogenic sulfate and changes in the rate of SO2 emissions over the industrial era.

Item #d94feb35

"An Empirical Analysis of the Strength of the Phytoplankton-Dimethylsulfide-Cloud-Climate Feedback Cycle," M.G. Lawrence (M. Planck Inst. Chem., 55020 Mainz, Ger.), J. Geophys. Res., 98(D11), 20,663-20,673, Nov. 20, 1993.

Develops an empirical model based on data relating the individual components of this proposed feedback. Estimates that the strength of the feedback is about 20% (10%-50%) of that necessary to completely counteract a perturbation to the global climate, such as that anticipated from greenhouse gases.

Item #d94feb36

"Large Contribution of Organic Aerosols to Cloud-Condensation-Nuclei Concentrations," T. Novakov (Lawrence Berkeley Lab., Berkeley CA 94720), J.E. Penner, Nature, 365(6449), 823-826, Oct. 28, 1993.

Uses data from a marine site known to be affected by anthropogenic emissions, to show that in such regions the role of organic aerosols in determining the climatic effect of clouds may be at least as important as that of sulfate aerosols.

Item #d94feb37

Two items from J. Geophys. Res., 98(D8), Aug. 20, 1993:

"Effect of Anthropogenic Sulfate Aerosols on Low-Level Cloud Albedo over Oceans," Y. Kim (NASA Goddard Inst. Space Studies, 2880 Broadway, New York NY 10025), R.D. Cess, 14,883-14,885. Satellite data demonstrate enhanced albedo off the east coasts of North America and Asia where anthropogenic sulfate is carried over the oceans. Similar trends are absent over ocean regions of the Southern Hemisphere removed from sulfate sources.

"Light Scattering and Cloud Condensation Nucleus Activity of Sulfate Aerosol Measured over the Northeast Atlantic Ocean," D.A. Hegg (Dept. Atmos. Sci., AK-40, Univ. Washington, Seattle WA 98195), R.J. Ferek, P.V. Hobbs, 14,887-14,894. Measurements suggest lower values for light scattering coefficient and sulfate cloud condensation nucleus efficiency than have been used in recent estimates of the climatic impact of sulfate aerosols, and suggest an important role for nonsulfate aerosol.

Item #d94feb38

"Cloud Processing of the Cloud Condensation Nucleus Spectrum and Its Climatological Consequences," K.N. Bower (Dept. Phys., Univ. Manchester Inst. Sci. & Technol., POB 88, Manchester M60 1QD, UK), T.W. Choularton, Quart. J. Royal Meteor. Soc., 119(512), 655-679, July 1993 (Part A).

Presents a modeling study of the effects of aqueous phase oxidation of sulfur by ozone and hydrogen peroxide. Although it indicates significant modification of the cloud condensation nucleus (CCN) spectrum emerging downwind of the processing cloud, the effect is expected to be important only on local scales close the source of new aerosol.

Item #d94feb39

"Twenty Years of Balloon-Borne Tropospheric Aerosol Measurements at Laramie, Wyoming," D.J. Hoffmann (CMDL, NOAA, 325 Broadway, Boulder CO 80303), J. Geophys. Res., 98(D7), 12,753-12,766, July 20, 1993.

A detailed examination of results from 265 high-altitude balloon flights shows evidence of a decreasing trend of 1.6-1.8% per year in the optically active tropospheric aerosol over the past 20 years, which may be related to a similar reduction in U.S. SO2 emissions.