System for Atmospheric Modeling

Model History

The System for Atmospheric Modeling, or SAM, has evolved from the Large-Eddy Simulation (LES) model that I coded while being a Ph.D. student at the University of Oklahoma. Coupled with the explicit or bin microphysics of Yefim Kogan, my Ph.D. advisor, the model has become a useful tool to study detailed cloud processes in the stratocumulus-topped boundary layers (Khairoutdinov and Kogan 1999). As part of my Ph.D thesis, I used the model to develop a bulk microphysics scheme for drizzling PBL clouds (Khairoutdinov and Kogan 2000).

Right after completing my PhD studies, in January 1998, I started my work at the Department of Atmospheric Science, Colorado State University, in David Randall's research group. At CSU, the model has undergone major overhaul both of code and physics. The explicit warm-cloud microphysics has been replaced with bulk microphysics that included the ice-microphysics processes. The thermodynamic prognostic variables have also been changed. The model has become suitable to run on massively parallel computers by using horizontal domain decomposition and employing the MPI communication protocol. The model's details can be found in Khairoutdinov and Randall (2003). In 2003, the model received its official name - SAM - with the version count starting from 6.0, reflecting the fact that SAM represents the sixth cloud-model design since 1987 when I started cloud modeling career at the Central Aerological Observatory (CAO) in the USSR.

Today, SAM is used by dozens cloud modelers in the United States and beyond. Incomplete list of publications of the scientific results obtained using SAM can be found at the end of this page.

Model Highlights