In the mid-1950s, the weather models used by
forecasters were still regional or continental (vs. hemispherical or
global) in scale. Calculations for numerical weather prediction were
limited to what could be accomplished in a couple of hours on
then-primitive digital computers. In addition, the time constraints
of analog/digital data conversion and long-distance communication
imposed limitations on the scale of operational weather
Yet for theoretical meteorologists -- unconcerned with real-time forecasting -- general circulation modeling became a kind of holy grail.
By mid-1955 Norman Phillips had completed a
2-layer, hemispheric, quasi-geostrophic computer
Despite its primitive nature, Phillips's model is now often regarded
as the first AGCM.
As computer power grew, the need for simplifying assumptions (such as barotropy and quasi-geostrophy) diminished. Many individuals throughout the developed world, including Phillips, began experiments with primitive equation models in the late 1950s. Between the late 1950s and the early 1960s, three separate groups began -- more or less independently -- to build many-leveled, three-dimensional AGCMs based on the primitive equations of Bjerknes and Richardson. Details of these efforts may be found at the links to each modeling group.
The first continuing effort to construct an
AGCM originated in 1955 as the General Circulation Research Section
of the U.S. Weather Bureau under the direction of Joseph
Smagorinsky felt that his charge was to continue with the final step of the von Neumann/Charney computer modeling program: a three-dimensional, global, primitive-equation general circulation model of the atmosphere. His laboratory, initially located in Suitland, Maryland (near the Weather Bureau's JNWP unit), later moved to Washington, D.C. In 1968, it stabilized at Princeton University as the Geophysical Fluid Dynamics Laboratory (GFDL), under the National Oceanic and Atmospheric Administration (NOAA), where it remains.
In 1959, Smagorinsky invited Syukuro Manabe of the University of Tokyo to join the lab. He assigned Manabe the task of GCM coding and development. With Smagorinsky and other members of the group, Manabe led one of the most vigorous and longest-lasting GCM development programs in the world. He retired in 1998, but remains active.
In the late 1950s, Yale Mintz of the UCLA Dept.
of Meteorology also began to design numerical general circulation
Like Smagorinsky, Mintz recruited a Japanese meteorologist, Akio
Arakawa, to help him build general circulation models. Arakawa, known
for his mathematical wizardry, was particularly interested in
building robust schemes for the parameterization of cumulus
convection. Mintz and Arakawa constructed a series of increasingly
sophisticated AGCMs beginning in 1961. IBM's Large Scale Scientific
Computation Department in San Jose, California, provided important
computational assistance and wrote the manual describing the
Of all the general circulation modeling groups in the world, the UCLA laboratory probably had the greatest influence on other modeling groups, especially in the 1960s and 1970s.
In 1960, Cecil E. "Chuck" Leith began work on
an AGCM at Lawrence Livermore National Laboratories. Trained as a
physicist, Leith became interested in atmospheric dynamics and
received the blessing of LLNL director Edward Teller for a project on
the general circulation. Teller's approval stemmed from his long-term
interest in weather modification.
After receiving encouragement from Jule Charney and spending a summer in Stockholm working up a simple model, Leith returned to Livermore and began to program his model on LLNL's supercomputers. Although aware of the Smagorinsky/Manabe and Mintz/Arakawa efforts, Leith worked primarily on his own. He had a working five-level model by 1961. However, he did not publish his work until 1965. Nevertheless, by about 1963 Leith had made a film showing his model's results in animated form and had given numerous talks about the model.
Leith ceased work on his model -- known as LAM ("Leith Atmospheric Model" or "Livermore Atmospheric Model") --in the mid-1960s, as he became increasingly issued in statistical modeling of turbulence. In 1968, he went to the National Center for Atmospheric Research, where he was instrumental in a number of climate modeling projects.
The National Center for Atmospheric Research, established in 1960, initiated an AGCM effort in 1964 under Akira Kasahara and Warren Washington.
By the early 1960s, Andrew Gilchrist and others at the UK Meteorological Office had also began building an AGCM. Their efforts were ultimately successful &emdash; although today they are almost unknown, probably because the researchers did not publish most of their work, except as internal memos. But the Met Office section within which they worked continued, evolving gradually into today's highly respected Hadley Centre for Climate Prediction and Research.
This points to a tantalizing historical question: were there other early AGCM efforts that have faded into obscurity?
The important role of carbon dioxide, water
vapor, and other "greenhouse" gases in the atmosphere's heat
retention capacity had been recognized in the 19th century
by the Swedish scientist Svante Arrhenius, who also speculated --
with remarkable prescience -- on the possibility of anthropogenic
climate change from the combustion of fossil fuels.
Little further work on the greenhouse effect was done until the late 1940s, when radioactivity in the atmosphere stimulated interest in "tracer" studies of various atmospheric constituent gases. This gradually led to a revival of interest in the possibility of anthropogenic influences on climate. During the International Geophysical Year (1957-58), Revelle and Suess proposed monitoring the carbon dioxide content of the atmosphere. This led to the establishment of Keeling's station at Mauna Loa in the same year, which soon established the regular annual increases in the carbon dioxide concentration.
Although these developments stimulated ongoing scientific interest, the greenhouse effect did not become a major research area until the latter half of the decade.
Atmospheric GCMs simulate the entire global circulation of the atmosphere. But they are not the only mathematical models useful in understanding the relationship between atmospheric composition and radiative transfer (the basis of the greenhouse effect). Other types of models used to study the greenhouse effect include energy-balance models, which compute global average surface temperature, and radiative-convective models, which calculate the vertical structure of the atmosphere. Each of these may have one or two dimensions.
In addition, models of the ocean circulation
(also called GCMs) play an increasingly crucial role in climate
While this Web site focuses exclusively on atmospheric GCMs, it is important not to lose sight of the other techniques in the modeling "hierarchy," which are frequently used as checks on AGCMs.
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N.A. Phillips, "The General Circulation of the Atmosphere: A
Numerical Experiment," Quarterly Journal of the Royal
Meteorological Society 82, no. 352 (1956): 123-164.
 K. Hinkelmann, "Ein numerisches Experiment mit den primitiven Gleichungen," in The Atmosphere and the Sea in Motion: Scientific Contributions to the Rossby Memorial Volume, eds. B. Bolin and E. Eriksson (New York: Rockefeller Institute Press, 1959), 486-500.
 J. Smagorinsky, "The Beginnings of Numerical Weather Prediction and General Circulation Modeling: Early Recollections," Advances in Geophysics 25 (1983): 3-37.
 S. Manabe, J. Smagorinsky, and R.F. Strickler, "Simulated Climatology of General Circulation with a Hydrologic Cycle," Monthly Weather Review 93, no. December (1965): 769-798.
S. Manabe and R. Wetherald, "Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity," Journal of the Atmospheric Sciences 24 (1967): 241-259.
J. Smagorinsky, S. Manabe, and J.L. Holloway, "Numerical Results from a Nine-Level General Circulation Model of the Atmosphere," Monthly Weather Review 93 (1965): 727-768.
 Y. Mintz, "Design of Some Numerical General Circulation Experiments," Bulletin of the Research Council of Israel 76 (1958): 67-114.
 W.E. Langlois and H.C.W. Kwok, "Description of the Mintz-Arakawa Numerical General Circulation Model," (Dept. of Meteorology, University of California at Los Angeles, 1969).
A. Arakawa, "Numerical Simulation of Large-Scale Atmospheric Motions," Numerical Solution of Field Problems in Continuum Physics (SIAM-AMS Proceedings, American Mathematical Society) 2 (1970): 24-40.
 C.E. Leith, "Numerical Simulation of the Earth's Atmosphere," in Methods in Computational Physics, eds. B. Alder, S. Fernbach, and M. Rotenberg (New York: Academic Press, 1965), 1-28.
 A. Gilchrist, "The Meteorological Office 5-Layer General Circulation Model," in W. L. Gates, ed., Report of the JOC Conference on Climate Models: Performance, Intercomparison, and Sensitivity Studies, Vol. 1 (Washington, D.C.: WMO/ICSU Joint Organizing Committee, Global Atmospheric Research Programme, 1979), 254-295.
 S. Arrhenius, "On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground," Philosophical Magazine and Journal of Science 41 (1896): 237-276.
 G.S. Callendar, "Can Carbon Dioxide Influence Climate?," Weather 4 (1949): 310-314.
H.E. Suess, "Natural Radiocarbon and the Rate of Exchange of Carbon Dioxide Between the Atmosphere and the Sea," in Nuclear Processes in Geologic Settings, ed. National Research Council Committee on Nuclear Science (Washington, D. C.: National Academy of Sciences, 1953), 52-56.
 G.N. Plass, "The Carbon Dioxide Theory of Climatic Change," Tellus 8 (1956): 140-154.
 R. Revelle and H.E. Suess, "Carbon Dioxide Exchange Between the Atmosphere and Ocean and the Question of an Increase of Atmospheric CO2 during the Past Decades," Tellus 9 (1957): 18-27.
 C.D. Keeling, "The Concentration and Isotopic Abundances of Carbon Dioxide in the Atmosphere," Tellus 12 (1960): 200-203.
 B. Bolin and E. Eriksson, eds., The Atmosphere and the Sea in Motion: Scientific Contributions to the Rossby Memorial Volume (New York: Rockefeller Institute Press, 1959).
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