The NCAR Community Climate Model (CCM3)

The NCAR Community Climate Model (CCM3) is no longer supported, use the Community Atmosphere Model (CAM) for the latest model that includes limited support for use of the community.

Nov 11 1998: Problem with packing on the SGI with CCM3.6

This message should be of interest to anyone running CCM3.6 on machines other than the CRAY PVP's at NCAR. It does *not* pertain to the more recent released code, CCM3.6.6.

There is a namelist-specifiable integer variable in the CCM called NDENS which allows one to pack history tapes at densities of 2 to 1 or 4 to 1. In CCM3.6, if this variable is set to a value other than 1 (i.e. packing is desired) and the packing library is not available (i.e. the platform is not an NCAR CRAY), the model will print a message stating that history tapes will not be packed. Unfortunately, in this case it will also fail to produce a usable history tape. Thus the moral of the story is: if running CCM3.6 on a machine other than an NCAR CRAY, don't set NDENS to a value other than 1 or you won't be able to read your history tapes.

In CCM3.6.6 however, the model will simply stop after printing the message. So there is no danger in this case of wasting vast amounts of computer time producing unreadable data.

CCM Core Group

Last modified: Nov/11/1998

Remember CCM3 is now unsupported, use CAM for the latest Atmospheric Model for use of climate science.

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