February 28, 2007
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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 5, NUMBER 2, FEBRUARY 1992
GLOBAL AND REGIONAL MODELING
Two items from J. Geophys. Res., 96(D12), Dec. 20, 1991:
"Three-Dimensional Simulation of 7Be in a Global Climate Model,"
R.A. Brost (M. Planck Inst. Chem., POB 3060, D-6500 Mainz, Ger.), J. Feichter,
M. Heimann, 22,423-22,445. Compares observed and simulated values of monthly and
annual average surface concentrations of 7Be using the Hamburg version of the
ECMWF model, as a test of wet scavenging parameterization.
"Three-Dimensional Modeling of the Concentration and Deposition of
210Pb Aerosols," J. Feichter (Meteor. Inst., Univ. Hamburg, Bundestr. 55,
WD-2000, Hamburg 13, Ger.), R.A. Brost, M. Heimann, 22,447-22,460. Employs a
version of the model used in the preceding paper, modified for better
climatological representation, to compare wet deposition simulation of 210Pb
(with a lower tropospheric source) to that of 7Be (with a stratospheric source).
Results suggest explicit representation of cumulous updrafts and scavenging from
them could improve mutual simulation of the two species.
"Quantitative Comparison between Simulated Cloudiness and Clouds
Objectively Derived from Satellite Data," E. Raustein (Geophys. Inst.,
Univ. of Bergen Allégt. 70, N-5007 Bergen, Norway), H. Sundqvist, K.B.
Katsaros, Tellus, 43A(5), 306-320, Oct. 1991.
Cloud cover and cloud liquid water content obtained from integration of a
limited area mesoscale model, with an elaborate condensation-cloud
parameterization scheme, are compared with corresponding quantities from AVHRR
and SSM/I satellite data. Demonstrates the value of this approach for diagnosing
the performance of the model's cloud parameterization.
"Regional-Scale Surface Hydrologic Simulations from Global Climate
Models: A Case Study," G. Thomas (Dept. Geog., Univ. British Columbia,
Vancouver, Can.), A. Henderson-Sellers, A.J. Pitman, Atmos.-Ocean, 29(3),
420-436, Sep. 1991.
Couples a regional-scale model, which has high spatial resolution and
realistic land-surface parameterization, to a global climate model, to derive
the detailed information on regional patterns of precipitation, moisture and
runoff required by water resource planners from climate change predictions.
Gives results for July for the Australian continent.
Two items from Nature, 353(6341), Sep. 19, 1991:
"Is Water Vapour Understood?" R.L. Jones (Dept. Chem., Univ.
Cambridge, Cambridge CB2 1EW, UK), J.F.B. Mitchell, p. 210. Discusses how
results of the following paper demonstrate the value of, and further need for,
accurate water vapor measurements in the upper troposphere, for assessing
"Wintertime Asymmetry of Upper Tropospheric Water between the Northern
and Southern Hemispheres," K.K. Kelly (Aeronomy Lab., NOAA, 325 Broadway,
Boulder CO 80303), A.F. Tuck, T. Davies, 244-247. Airborne measurements of total
water (vapor plus ice crystal) show that the upper troposphere in middle,
subpolar and high latitudes is a factor of 2-4 drier during austral winter than
during boreal winter, a feature climate models must be able to reproduce. This
implies a corresponding asymmetry in the production rate of the hydroxyl
radical, and in related chemical processes such as methane loss.
"An Intercomparison of Model and Observed Global Precipitation
Climatologies," M. Hulme (Clim. Res. Unit, Univ. E. Anglia, Norwich NR4
7TJ, UK), Geophys. Res. Lett., 18(9), 1715-1718, Sep. 1991.
Three independently maintained precipitation climatologies are used to
evaluate the performance of six GCMs: GFDL, GISS, Lawrence Livermore, Oregon
State, and UK Meteorological Office (high and low resolution). Observed monthly
precipitation over both land and ocean areas is best simulated by the high
resolution UK model; for low resolution models, UK is better than GISS, GFDL and
"An Energy Balance Climate Model with Hydrologic Cycle," V.
Jentsch (Rheinisch-Westfälische Technische Hochschule Aachen,
Augustinerbach, 5100 Aachen, Ger.), J. Geophys. Res., 96(D9),
Sep. 20, 1991.
"1. Model Description and Sensitivity to Internal Parameters,"
17,169-17,179. Presents a thermodynamic, time-latitude model, designed to
illustrate the effect of a hydrological cycle on climate sensitivity, which has
three climatic variables: temperatures of an idealized ocean and atmosphere, and
atmospheric humidity. The sensitivity of the model is governed by radiation
parameters, especially cloud albedo.
"2. Stability and Sensitivity to External Forcing," 17,181-17,193.
Two stable equilibrium points are found corresponding to the present warm
climate and a cold climate. The model is quite stable to external forcing: the
solar constant must be reduced about 20% to obtain total ice cover; atmospheric
CO2 must be doubled to obtain 1.5° C warming.
"A Simple Parameterization of Sub-Grid Scale Open Water for Climate
Models," A.J. Pitman (Earth Sci., Macquarie Univ., N. Ryde, 2109 NSW,
Australia), Clim. Dynam., 6(2), 99-112, Sep. 1991. Application
of the scheme, which permits any land surface model to be modified to account
for open water, indicates that the impact of the modification is large enough to
warrant incorporation into climate models.
"Glacial pCO2 Reduction by the World Ocean: Experiments with the
Hamburg Carbon Cycle Model," C. Heinze (Inst. Meereskunde, Univ. Hamburg,
Troplowitzstr. 7, D-2000 Hamburg 54, Ger.), E. Maier-Reimer, K. Winn, Paleoceanog.,
6(4), 395-430, Aug. 1991.
With sensitivity experiments, investigated the role of chemical and
biological parameters and different circulation regimes in the 80 ppm reduction
of atmospheric CO2 during the last glaciation. None of the experiments alone
could explain all observed tracer changes; more effort should be devoted to
realistically reproducing the ice age ocean circulation field, making use of the
forthcoming glacial radiocarbon data base.
"Transient Responses of a Coupled Ocean-Atmosphere Model to Gradual
Changes of Atmospheric CO2. Part I: Annual Mean Response," S. Manabe (GFDL,
Princeton Univ., POB 308, Princeton NJ 08542), R.J. Stouffer et al., J.
Clim., 4(8), 785-818, Aug. 1991.
The model, with global geography and seasonal variation of insolation, was
integrated for gradually increasing, constant, and gradually decreasing CO2
concentrations. The time-dependent responses of global mean surface air
temperature are similar in magnitude for the increasing and decreasing CO2
cases, despite certain asymmetries in the respective responses of the model
Two comments by C. Covey (Lawrence-Livermore Nat. Lab., POB 808,
Livermore CA 94550):
"Credit the Oceans?" Nature, 352(6332), 196-197,
July 18, 1991. Discusses how recent modeling results by the author and by Rind
and Chandler emphasize the need for further coupled ocean-atmosphere modeling to
understand climate change.
"Ocean Uncertainty," ibid., 353(6342), 309-310,
Sep. 26, 1991. Presents brief results that make a case for diagnosis and
intercomparison of oceanic general circulation models, emphasizing rate of
response to external perturbations.
"Stability and Variability in a Coupled Ocean-Atmosphere Climate
Model: Results of 100-Year Simulations," D.D. Houghton (Dept. Meteor.,
Univ. Wisconsin, 1225 W. Dayton St., Madison WI 53706), R.G. Gallimore, L.M.
Keller, J. Clim., 4(6), 557-577, June 1991.
Two simulations, one with a low resolution atmospheric GCM coupled to a
mixed-layer ocean formulation and the other with the GCM forced by prescribed
ocean conditions, were compared to assess the effects of an interactive ocean
and sea-ice component on the stability and interannual variability of a climate
system. Including the interactive ocean produced a red spectrum in surface
temperature but not in 700 mb temperature, because of the effects of longwave
cooling and atmosphere-ocean energy exchange.
"The Response of a General Circulation Model to Cloud Longwave
Radiative Forcing. II: Further Studies," J.M. Slingo (Dept. Meteor., Univ.
Reading, Reading RG6 2AU, UK), A. Slingo, Quart. J. Roy. Meteor. Soc.,
117(498), 333-364, Jan. 1991 Pt. B.
Sensitivity to the vertical profile of forcing was assessed by replacing the
cloud prediction scheme in the NCAR model with one from the ECMWF model. Results
confirm those of Part 1 and emphasize the influence of tropical cirrus clouds.
Perturbations to diabatic heating over South America may have an important
influence on the Walker circulation and extra-tropical flow; implications for
the tropical deforestation problem are discussed.
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