A cloud resolving model as a cloud parameterization in the NCAR Community Climate System Model: Preliminary results

Preliminary results of a short climate simulation with a 2-D cloud resolvin g model (CRM) installed into each grid column of an NCAR Community Climate System Model (CCSM) are presented. The CRM replaces the conventional convec tive and stratiform cloud parameterizations, and allows for explicit comput ation of the global cloud fraction distribution for radiation computations. The extreme computational cost of the combined CCSM/CRM model has thus far limited us to a two-month long climate simulation (December-January) using 2.8 degrees x 2.8 degrees resolution. The simulated geographical distribut ions of the total rainfall, precipitable water, cloud cover, and Earth radi ation budget, for the month of January, took very reasonable.