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 11, NUMBER 3, MARCH 1998

PROFESSIONAL PUBLICATIONS...
RADIATIVE FORCING

Item #d98mar100

"Growth of Fluoroform (CHF3, HFC-23) in the Background Atmosphere," D.E. Oram (Sch. Environ. Sci., Univ. E. Anglia, Norwich NR4 7TJ, UK; e-mail: D.E.Oram@uea.ac.uk), W.T. Sturges et al.,Geophys. Res. Lett., 25(1), 35-38, Jan. 1, 1998.

Presents the first assessment of this important, unregulated greenhouse gas, which is increasing in the atmosphere at a rate of 5% per year. It has a long atmospheric lifetime, and its cumulative emissions through 1995 have a global warming equivalent to 1.6 billion tons of CO₂.

Item #d98mar101

"Radiative Forcing Due to Tropospheric Ozone and Sulfate Aerosols," R. van Dorland (Royal Neth. Meteor. Inst., POB 201, 3730 AE De Bilt, Neth.; e-mail: dorland@knmi.nl), F.J. Dentener, J. Lelieveld,J. Geophys. Res., 102(D23), 28,079-28,100, Dec. 20, 1997.

Combines a radiative wideband model with calculations of tropospheric ozone and sulfate aerosols from a 3-D chemistry/transport model, to examine preindustrial (1850), contemporary, and future (2050) conditions. Global and annual average radiative forcings approximately balance over the industrial period (1850-1990). The positive radiative forcing of ozone is expected to increase by another 70% over the period 1990-2050; the negative forcing of sulfate aerosols is predicted to increase even more (150%). Maximum changes of both constituents are moving southward in the Northern Hemisphere as a result of emerging economies.

Item #d98mar102

"Atmospheric Radiation and Atmospheric Humidity," J.E. Harries (Blackett Lab., Univ. London, London SW7 2BZ, UK),Quart. J. Royal Meteor. Soc., 123(544), 2173-2186, Oct. 1997 Part B.

Evaluates two satellite humidity data sets (HALOE and TOVS) and compares with GCM simulations. Shows that uncertainties of only a few percent in the humidity distribution could produce changes in the outgoing spectrum of magnitude similar to that caused by a doubling CO₂. Errors in the water vapor amounts generated in model simulations of climate could therefore be significant.

Item #d98mar103

"Possible Change in Climate Parameters with Zero Net Radiative Forcing," A. Sinha (Blackett Lab., Univ. London, London SW7 2BZ, UK; e-mail: ashok.sinha@ic.ac.uk), J.E. Harries,Geophys. Res. Lett., 24(19), 2355-2358, Oct. 1, 1997.

Calculations show that even when simultaneous aerosol and CO₂ perturbations cancel and net radiative forcing is zero, heating rates within the atmosphere and surface radiation characteristics may still be substantially altered. In view of the effect of radiative heating on atmospheric motions, and the dependence of biological systems on insolation, the effects of climate change need to be quantified even when the mean radiative forcing at all locations is unchanged.

Item #d98mar104

"Decline in Global Solar Radiation with Increased Horizontal Visibility in Germany Between 1964 and 1990," B.G. Liepert (Lamont-Doherty Earth Observ., Rte. 9W, Palisades NY 10964; e-mail: liepert@ldeo.columbia.edu), G.J. Kukla,J. Clim., 10(9), 2391-2401, Sep. 1997.

Global solar radiation at all sky conditions throughout much of the diurnal insolation cycle declined at all stations except one. Results are believed to be reasonably representative of rural, industrial and urban environments of Europe.

Item #d98mar105

"Radiative Forcing of Climate Change by CFC-11 and Possible CFC Replacements," N. Christidis (Dept. Meteor., Univ. Reading, Reading RG6 6BB, UK; e-mail: N.Christidis@reading.ac.uk), M.D. Hurley et al.,J. Geophys. Res., 102(D16), 19,597-19,609, Aug. 27, 1997.

Calculations indicate a value of radiative forcing for CFC-11 that is 30% higher than the value adopted by the IPCC, and is believed to be accurate to within 10%.

Item #d98mar106

"Radiative Forcing Calculations for CH3Cl and CH3Br," A.S. Grossman (Atmos. Sci., Livermore Natl. Lab., L-103, Livermore CA 94550; e-mail: allen@seneca.llnl.gov), K.E. Grant et al.,J. Geophys. Res., 102(D12), 13,651-13,656, June 27, 1997.

Calculations indicate that methyl chloride and methyl bromide have direct global warming potentials similar to that of methane, but current emission rates are too low to contribute meaningfully to atmospheric greenhouse warming.

Item #d98mar107

"Simulation of the Meridionally and Seasonally Varying Climate Response Caused by Changes in Ozone Concentration," R. Bintanja (Inst. Marine Res., POB 80005, 3508 TA Utrecht, Neth; e-mail: r.bintanja@fys.ruu.nl), J.P.F. Fortuin, H. Kelder,J. Clim., 10(6), 1288-1311, June 1997.

Experiments with a simplified climate model show that the net effect of tropospheric ozone increases and stratospheric ozone depletion is a slight global average cooling (0.001 to 0.003 K per year), which offsets by about 10% the projected surface warming due to increases in the other greenhouse gases.

Item #d98mar108

"Radiative Forcing and Temperature Trends from Stratospheric Ozone Changes," P.M. de F. Forster (Dept. Meteor., Univ. Reading, Reading RG6 6BB, UK; e-mail: piers@met.rdg.ac.uk), K.P. Shine,J. Geophys. Res., 102(D9), 10,841-10,855, May 20, 1997.

Uses sophisticated radiative transfer schemes and new estimates of ozone trends to update estimates of stratospheric ozone radiative forcing. The stratospheric ozone changes may have offset about 30% of the forcing due to increases in well-mixed greenhouse gases since 1979, and about 15% of the forcing since 1964, at least on a global and annual mean.

Item #d98mar109

"An Estimation of the Climatic Effects of Stratospheric Ozone Losses during the 1980s," R.M. MacKay (Clark College, Vancouver WA 98663), M.K.W. Ko et al.,J. Clim., 10(4), 774-788, Apr. 1997.

Calculations with a high spatial resolution, seasonal, radiative-dynamical model show that changes in stratospheric ozone between 1979 and 1990 lowered greenhouse warming by about 39%. This estimate is higher than the 28% compensation previously estimated using a lower resolution model.

Item #d98mar110

"Radiative Forcing of the Earth's Climate System Due to Tropical Tropospheric Ozone Production," R.W. Portmann (NOAA-ARL, R/E/AL8, 325 S. Broadway, Boulder CO 80303; e-mail: bportmann@al.noaa.gov), S. Solomon et al.,J. Geophys. Res., 102(D8), 9409-9417, Apr. 27, 1997.

Uses several methods to conclude that widespread radiative forcing of at least 0.5 to 1 W m-2 exists over large areas of the tropics for much of the year. This forcing is comparable in magnitude but opposite in sign to estimates of aerosol forcing from tropical biomass burning, but the burning contribution to ozone affects a larger area. Effects of tropical ozone changes could be significant for evaluation of both regional and global anthropogenic forcing of climate.

Item #d98mar111

"Radiative Forcing and Climate Response," J. Hansen (NASA Goddard Inst. Space Studies, 2880 Broadway, New York NY 10025; e-mail: jhansen@giss.nasa.gov), M. Sato, R. Ruedy,J. Geophys. Res., 102(D6), 6831-6864, Mar. 27, 1997.

Examines the sensitivity of a climate model to a wide range of radiative forcings. In general, the global mean temperature change can vary by 50% or more depending on the characteristics of the forcing other than its magnitude, such as altitude or time of day. Nevertheless, results reaffirm the value of the radiative forcing concept for predicting climate response and comparing different forcings. Halogen-driven ozone depletion may have offset more than half the radiative forcing since 1979 due to well-mixed greenhouse gases.

Item #d98mar112

"Earth's Annual Global Mean Energy Budget," J.T. Kiehl (NCAR, POB 3000, Boulder CO 80307; e-mail: jtkon@ncar.ucar.edu), K.E. Trenberth,Bull. Amer. Meteor. Soc., 78(2), 197-208, Feb. 1997.

A review and synthesis that offers a new estimate of the energy budget. Emphasizes the uncertainties and issues involved in determining the numbers, in order to focus attention on the need for improvements that will lead to strong, observationally-based constraints for global climate models.