GCMs: General Circulation Models We use a variety of GCMs for our research, from dry atmosphere models to relatively complex coupled atmosphere-ocean models. The GCMs we use are built using the Flexible Modeling System (FMS) of NOAA’s Geophysical Fluid Dynamics Laboratory. For idealized GCMs, we use the FMS dynamical core (that is, the basic numerical schemes FMS provides for the hydrostatic primitive equations), with various idealizations for the lower boundary conditions, for radiative transfer, and for moist or dry convection. Several dry and moist idealized GCMs are available in a source tree here. A README file describes the structure of the tree and contains rudimentary instructions on how to run the models; a CHANGES file describes recent changes. The entire tree is also available as zip archive. The models were developed with support by the U.S. National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA).