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Email: pedwards at stanford dot edu

Center for International Security and Cooperation
Freeman Spogli Institute
C226 Encina Hall
616 Serra St
Stanford, CA 94306-6165

Office: 650.725.2707
Fax: 206.337.1523

The Livermore Atmospheric Model (LAM)

LLNL Models:

In 1960, Cecil E. "Chuck" Leith began work on a GCM 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, Leith spent a summer in Stockholm at the Swedish Institute of Meteorology. There he coded a five-level GCM for LLNL's newest computer, the Livermore Automatic Research Calculator (LARC), due to be delivered in the fall of 1960. Leith wrote the code based on the manual for the new machine.

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.[1] 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.

View part of Leith's 1963 model animation

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.

LAM: Model Characteristics

The initial model was based on the Bjerknes/Richardson primitive equations. It had five vertical levels and used a 5° x 5° horizontal grid. It covered only the northern hemisphere, with a "slippery wall" at 60°N. In order to damp the effects of small-scale atmospheric waves, Leith introduced an artificially high viscosity, which caused serious problems and stimulated Leith's career-long interest in turbulence problems.

{link to Leith interview?}

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[1] 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.

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