Evaluation of Simulated Clouds and Radiation at the ARM Site

Ghan, S. J., Pacific Northwest National Laboratory

General Circulation and Single Column Models/Parameterizations

Cloud Modeling

Ghan, S.J. and Leung, L.R., 1999: "A Comparison of Three Different Modeling Strategies for Evaluating Cloud and Radiation Parameterizations," Monthly Weather Review 127( 9): 1967-1984.

Observed and Simulated Column Water Vapor

Column Cloud Water


Surface Downward Longwave Radiation

Surface Downward Solar Radiation

One of the primary goals of the ARM Program is to use surface measurements to evaluate cloud and radiation parameterizations for global circulation models. One of the primary tools for evaluating cloud and radiation parameterizations is the Single Column Model driven by observed vertical velocity and horizontal advective tendencies of temperature and humidity. Other tools are regional and global circulation models nudged toward observed winds.

We have driven a Single Column Model (SCM), a Regional Circulation Model (MM5), and a Global Circulation Model (CCM2) by observed winds for the period October 25 - November 14, 1995. The treatment of physical processes is virtually the same in each model.

The simulated and observed fields agree at some times and disagree at others. The fields simulated by each model agree at some times and disagree at others. Further experiments are needed to sort out reasons for differences.