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 4, NUMBER 7, JULY 1991

PROFESSIONAL PUBLICATIONS...
GLOBAL MODELING

Item #d91jul22

Special Section: "The Intercomparison of Radiation Codes in Climate Models," J. Geophys. Res., 96(D5), May 20, 1991. The ICRCCM was initiated by the World Climate Research Program and the International Association of Meteorology and Atmospheric Physics to accomplish such goals as developing a better understanding of the differences in model approaches, understanding how these differences affect model sensitivity, evaluating the effects of simplifying assumptions, and evaluating the effects of using different sources of spectral line data.

The first of 15 papers, an overview by R.G. Ellingson and Y. Fouquart (pp. 8925-8927) gives the history and objectives, summary of results to date and initial recommendations. Over the last four years, the differences in results have been narrowed as errors were found in some codes and as the understanding of many modeling problems increased. The group has recommended that ICRCCM test cases be used to test radiation algorithms prior to application to climate-related problems. Because the large discrepancies cannot be resolved through further calculation, the group has recommended that spectral radiance be measured at high spectral resolution simultaneously with the atmospheric data needed to calculate radiances.

Item #d91jul23

J. Geophys. Res., 96(D5), May 20, 1991.

"Upper Limit for Sea Ice Albedo Feedback Contribution to Global Warming," C. Covey (Atmos. Sci. Div., Lawrence Livermore Nat. Lab., POB 808, Livermore CA 94551), K.E. Taylor, R.E. Dickinson, 9169-9174. Results using the NCAR climate model suggest that for greenhouse gas warming equivalent to doubling CO₂ or greater, the sea ice albedo feedback is likely to be smaller than that from water vapor and potentially smaller than that from clouds.

"Effects of Surface Temperature and Clouds on the CO₂ Forcing," C. Schmitt (Dept. Atmos. Sci., Colorado State Univ., Ft. Collins CO 80523), D.A. Randall, 9159-9168. Based on a pair of perpetual July simulations, using the Colorado State general circulation model, in which the sea surface temperatures differed by 4 K, found that clouds reduce the CO₂ forcing of the surface-troposphere system by at least 0.59 W m-2.

Item #d91jul24

J. Geophys. Res., 96(D4), Apr. 20, 1991.

"Development of a Two-Dimensional Global Tropospheric Model: Model Chemistry," A.M. Hough (Environ. Sci. Div., Harwell Lab., Didcot, Oxfordshire OX11 0RA, UK), 7325-7362. Used a latitudinally averaged model to study the distributions, budgets and trends of trace gases in the atmosphere from pole to pole and from the surface to 24 km. The chemical mechanism used contains 56 chemical species. Model results are generally in good agreement with observations, reproducing the observed temporal and spatial variation in the mixing ratios of CH₄, CO, O3 and hydrocarbons. They also suggest that the observed increase in the mixing ratio of CH₄ may be due not only to an increasing source strength, but also to a downward perturbation in OH radical abundance.

"Increased Ocean Heat Transports and Warmer Climate," D. Rind (NASA-Goddard, 2880 Broadway, New York NY 10025), M. Chandler, 7437-7461. Effects of increased transports on climate were studied using the GISS GCM. The increases used amounted to 15% on the global average and were sufficient to melt all sea ice at high latitudes, resulting in a global climate 2° C warmer. The large high-latitude amplification associated with ocean heat transport and sea ice changes differs from that predicted for increased trace gases, for which water vapor increase is the primary feedback mechanism. The warming of the 1930s looks more like the altered ocean heat transport signal, while the warming of the 1980s is more like the trace gas effect.

Item #d91jul25

"Infrared Radiation Parameterizations in Numerical Climate Models," M.-D. Chou (NASA-Goddard, Code 913, Greenbelt MD 20771), D.P. Kratz, W. Ridgway, J. Clim., 4(4), 424-437, Apr. 1991. Presents various approaches for parameterizing broadband transmission functions of several trace gases.

Item #d91jul26

"A Simplified Biosphere Model for Global Climate Studies," Y. Xue (Ctr. Ocean-Land-Atmos. Interactions, 2213 Comp. & Space Sci. Bldg., Univ. Maryland, College Pk. MD 20742), P.J. Sellers et al., J. Clim., 4(3), 345-364, Mar. 1991. Three major reductions have been achieved in a previously described simple biosphere model for use in GCMs.

Item #d91jul27

"An Eddy-Resolving Model of the Southern Ocean," The FRAM Group (c/o D.J. Webb, Inst. Oceanog. Sci., Deacon Lab., Godalming, Surrey GU8 5UB, UK), Eos, pp. 169, 174-175, Apr. 9, 1991. The model shows that eddy resolution leads to significant improvement of some of the processes related to global climate change, such as deep convection at high latitudes.

Item #d91jul28

Clim. Dynamics, 5(3), 135-143, Mar. 1991.

"A Comparative Study of the Observations of High Clouds and Simulations by an Atmospheric General Circulation Model," R.T. Wetherald (GFDL/NOAA, Prince-ton Univ., POB 308, Princeton NJ 08542), V. Ramaswamy, S. Manabe, 135-143. The GFDL model tested appears to capture the principal large-scale features of the tropical convective processes evident in satellite and precipitation data sets, particularly the generation of upper tropospheric cirrus clouds, which greatly affect climate.

"Sensitivity of an Atmospheric General Circulation Model to Prescribed SST Changes: Feedback Effects Associated with the Simulation of Cloud Optical Properties," H. Le Treut (Lab. Météor. Dynam. CNRS, école Normale Supérieure, 24 rue Lhomond. F-75231 Paris Cedex 05, France), Z.-X. Li, 175-187. When a prognostic budget equation is used to predict cloud condensed water and cloud optical properties within a GCM, the model performance is reasonable, except that the stratus clouds are not correctly simulated. The model's response to prescribed changes in the sea surface temperature is studied, and the nature of the cloud simulation problem analyzed.

Item #d91jul29

"Surface Energy Balances of Three General Circulation Models: Implications for Simulating Regional Climate Change," W.J. Gutowski Jr. (Atmos. & Environ. Res. Inc., 840 Memorial Dr., Cambridge MA 02139), D.S. Gutzler, W.-C. Wang, J. Clim., 4(2), 121-134, Feb. 1991.

Energy balances were compared for current climatic conditions and for a doubling of CO₂ to assess uncertainty in model performance and to diagnose the radiative and thermodynamic processes responsible. The large-scale mechanisms of greenhouse warming are not very sensitive to the precise surface balance of heat in the models; regional-scale simulations will not improve unless discrepancies in global-average longwave radiation are resolved; differences in how the models handle moisture in the atmosphere and in the ground are important.

Item #d91jul30

"A Study of the Sources and Sinks of Methane and Methyl Chloroform Using a Global Three-Dimensional Lagrangian Tropospheric Tracer Transport Model," J.A. Taylor (CIRES, Univ. Colorado, Boulder CO 80309), J. Geophys. Res., 96(D2), 3013-3044, Feb. 20, 1991.

This extensive investigation was done in part to resolve inconsistencies between published CH3CCl3 emissions data for 1981-1984 and observed CH3CCl3 concentration increases. Results suggest that either the assumption that a uniform fraction of net primary productivity is converted to CH₄ is not valid for rice paddies, or that this quantity is underestimated for rice paddies, or that present CH₄ emission estimates from rice paddies are too high.

Item #d91jul31

"Biological Production Models as Elements of Coupled Atmosphere-Ocean Models for Climate Research," T. Platt (Biol. Oceanog. Div., Bedford Inst. Oceanog., POB 1006, Dartmouth, NS B2Y 4A2, Can.), S. Sathyendranath, J. Geophys. Res., 96(C2), 2585-2592, Feb. 15, 1991. Process models of phytoplankton production are discussed with respect to their suitability for incorporation into global-scale numerical ocean circulation models.

Item #d91jul32

"Cloud-Radiation Interactions in a General Circulation Model: Impact upon the Planetary Radiation Balance," L.D. Smith (NCAR, POB 3000, Boulder CO 80307), T.H. Vonder Haar, J. Geophys. Res., 96(D1), 893-914, Jan. 20, 1991.

The unique multimonth set of simultaneous Earth radiation budget observations and cloud amount estimates from the Nimbus 7 satellite was used to validate a long-term climate simulation with the NCAR climate model, and to identify a major difficulty with the model. The standard deviations of the model-generated cloud and radiation fields were overestimated by about a factor of two over the whole globe, in part because of reduced interactions between clouds and the hydrologic cycle. The impact of clouds is crucial, and stronger couplings between the various physical processes in the NCAR model are needed.

Item #d91jul33

"Simple Model Representation of Atmosphere-Ocean GCMs and Estimation of the Time Scale of CO₂-Induced Climate Change," M.E. Schlesinger (Dept. Atmos. Sci., Univ. Illinois, 105 S. Gregory Ave., Urbana IL 61801), X. Jiang, J. Clim., 3(12), 1297-1315, Dec. 1990.

Developed a simple atmosphere-ocean model capable of representing the 20-year 1 x CO₂ and 2 x CO₂ simulations obtained with a coupled atmosphere-ocean GCM, to estimate the characteristic response time of the climate system that accounts for ocean upwelling. The model was used to project the response of the coupled atmosphere-ocean GCM from year 20 to year 100; the characteristic response time is between 40 and 60 years--in close agreement with estimates of Schlesinger et al.

Item #d91jul34

"Atmospheric Response to Ice Age Conditions: Climatology Near the Earth's Surface," M. Lautenschlager (Max Planck Inst. Meteor., Bundesstr. 55, D-2000, Hamburg 13, Ger.), K. Herterich, J. Geophys. Res., 95(D13), Dec. 20, 1990. A six-year simulation of the ice age atmosphere, using the GCM of the European center for Medium Range Weather Forecasts, suggests that such models are able to describe climates in the distant past, although internal parameterizations are tuned to present data sets.

Item #d91jul35

"Greenhouse Warming: Is the Mid-Holocene a Good Analogue?" J.F.B. Mitchell (Hadley Ctr., Meteor. Off., London Rd., Bracknell, Berks RG12 2SZ, UK), J. Clim., 3(11), 1177-1192, Nov. 1990.

The mid-Holocene (9000-6000 years before present) is often suggested as an analogue for enhanced greenhouse warming, although the changes in net radiative forcing at the top of the atmosphere are very different in the two cases. Two climate model experiments, one in which CO₂ amounts are doubled and the other in which the value of the Earth's orbital parameters are altered, are compared. Assuming that the gross behavior of the model is realistic, the Holocene is not a good analogue.

Item #d91jul36

"A Method of Relating General Circulation Model Simulated Climate to the Observed Local Climate. Part I: Seasonal Statistics," T.R. Karl (Nat. Clim. Data Ctr., Fed. Bldg., Ashville NC 28801), W.-C. Wang et al., J. Clim., 3(10), 1053-1079, Oct. 1990. Presents a method based on three statistical techniques, and demonstrates it using the Oregon State University two-level atmospheric GCM.

Item #d91jul37

"Use of a Limited-Area Model Nested in a General Circulation Model for Regional Climate Simulation over Europe," F. Giorgi (NCAR, POB 3000, Boulder CO 80307), M.R. Marinucci, G. Visconti, J. Geophys. Res., 95(D11), 18,413-18,431, Oct. 20, 1990.

Owing to its better representation of topography and coastlines, the nested Penn. State Univ./NCAR mesoscale model produces regional distributions of variables (such as precipitation, surface air temperature, cloudiness and snow cover) which are much more realistic than those of the driving GCM alone and compare well with high resolution observations.

Item #d91jul38

"Intercomparison and Interpretation of Climate Feedback Processes in 19 Atmospheric General Circulation Models," R.D. Cess (State Univ. New York, Stony Brook NY 11794), G.L. Potter et al., ibid., 95(D10), 16,601-16,615, Sep. 20, 1990.

The intercomparison used sea surface temperature change as a surrogate for climate change and focused on cloud climate interactions. A roughly threefold variation in one measure of global climate was found among the models, most of which was attributable to differences in the depiction of cloud feedback. If the models are to be used as reliable climate predictors, their treatment of clouds must be improved.

Item #d91jul39

"Predicting Generalized Ecosystem Groups with the NCAR CCM: First Steps towards an Interactive Biosphere," A. Henderson-Sellers, (Sch. Earth Sci., Macquarie Univ., N. Ryde, NSW 2109, Australia), J. Clim., 3(9), 917-940, Sep. 1990.

Canopy-plus-soil "big-leaf" models of the land surface that now exist could be the basis for incorporation of an interactive land biosphere into global models. However, their use depends upon satisfactory specification of the distribution of plants and soils, which must be manufactured for altered climatic scenarios. As an alternative, a highly generalized (nine class) grouping of Holdridge life zones has been used to investigate three-step "coupling" of a land surface scheme into a global climate model.

Item #d91jul40

"Review: Improvements in General Circulation Model Performance in Simulating Antarctic Climate," I. Simmonds (Dept. Meteor., Univ. Melbourne, Parkville, Victoria 3052, Australia), Antarctic Sci., 2(4), 287-300, 1990.

Tracing the changes in the ability of GCMs used over the last two decades to simulate climate at high southern latitudes has revealed a steady improvement in model products. The task of assessing model climates in high southern latitudes is made difficult by uncertainties in the data used for climatological statistics. There is obviously a need for improvements in both modeling and observations.

Item #d91jul41

"Internal Secular Variability in an Ocean General Circulation Model," U. Mikolajewicz (Max Planck Inst. Meteor., Bundesstr. 55, D-2000, Hamburg 13, Ger.), E. Maier-Reimer, Clim. Dynamics, 4(3), 145-156, Sep. 1990. The Hamburg Ocean GCM exhibits pronounced variability in a frequency band around 320 years, which could complicate interpretation of anthropogenic climate modification.

Item #d91jul42

"Sensitivity of Regional Climates to Localized Precipitation in Global Models," A.J. Pitman (Sch. Earth Sci., Macquarie Univ., N. Ryde, NSW 2109, Australia), A. Henderson-Sellers, Z.-L. Yang, Nature, 346(6286), 734-737, Aug. 23, 1990. Shows that continental and surface climatologies and climate change predictions for tropical forest ecotypes derived from GCMs may be very sensitive to slight modifications in the land-surface/atmosphere coupling. Climate studies using near-surface output from such simulations may therefore be misleading.

Item #d91jul43

"CO₂ Climate Sensitivity and Snow-Sea-Ice Albedo Parameterization in an Atmospheric GCM Coupled to a Mixed-Layer Ocean Model," G.A. Meehl (NCAR, POB 3000, Boulder CO 80307), W.M. Washington, Clim. Change, 16(3), 283-306, June 1990. Highlights an uncertainty associated with results from current climate GCMs that use highly parameterized snow-sea-ice albedo schemes with simple mixed-layer ocean models.

Item #d91jul44

"Computational Aspects of Moisture Transport in Global Models of the Atmosphere," P.J. Rasch (addr. immed. above), D.L. Williamson, Quart. J. Roy. Meteor. Soc., 116B, 1071-1090, July 1990.

Highlights the computational problems which still exist within the better numerical methods used to simulate the transport of water vapor, and demonstrates the care with which computational constraints must be applied to the solution. The spectral and semi-Lagrangian transport schemes produce very different climatologies in model simulations.

Item #d91jul45

"Atmospheric Trace Gases and Global Climate: A Seasonal Model Study," W.-C. Wang (Atmos. Sci. Res. Ctr., State Univ., 100 Fuller Rd., Albany NY 12205), G. Molnar, et al., Tellus, 42B(2), 149-161, Apr. 1990.

Calculations, using projected trends of CO₂, N₂O, CH₄, and CFCs, showed that the annual global mean surface temperature could warm by as much as 2.5° C, with larger warming at high latitudes, by the middle of the next century. Warming in the lower stratosphere and upper troposphere would be much larger than at the surface.

Item #d91jul46

"The Performance of Physically Based Cloud Schemes in General Circulation Models," E. Heise (Deutscher Wetterdienst, Offenbach, Ger.), E. Roeckner, Beitr. Phys. Atmos., 63(1), 1-14, Feb. 1990. The schemes implemented in the University of Hamburg GCM (using water budget equations) and in the Deutscher Wetterdienst GCM (based on a statistical cloud model) are both able to reproduce the gross features of observed climatological cloudiness, the radiation budget and cloud radiation interaction.

Item #d91jul47

"Parameterization for the Absorption of Solar Radiation by O2 and CO₂ with Application to Climate Studies," M.-D. Chou (Code 613, NASA-Goddard, Greenbelt MD 20771), J. Clim., 3(2), 209-217, Feb. 1990. Application of simple and accurate parameterizations in a zonally averaged multilayer energy balance model show that the absorption of solar radiation due to O2 and CO₂ has a small but non-negligible effect on climate. This effect should be included in climate studies using numerical models.