CESM Models

What is CCSM3.0.1 beta14?


ccsm3.0.1 beta14 is an "internal beta version" in the ccsm3.0 line of development, it is *not* an official "public release".

Following the public release of ccsm3.0 in June, 2004, the CCSM Software Engineering Group (CSEG) has continued to do a limited amount of development on the ccsm3.0 code base with a goal of adding support for new machines and fixing bugs while maintaining the same climate as produced by the original release. The result of this development is a sequence of ccsm3.0.1 "internal beta versions", a sequence that might eventually result in a ccsm3.0.1 "public release". Unfortunately, due to staff shortages, it's unclear if and when such a public release will ever be created.

CSEG may, however, make certain internal beta versions of ccsm3.0.1 available as a way to give community access to machine upgrades and bug fixes. ccsm3.0.1 beta14 is one of those internal beta versions.

We want to stress, however, that due to the limited testing associated with internal beta versions, we cannot assure the robustness or scientific validity of this code, as was done for the ccsm3.0 release.

What is different about ccsm3.0.1 beta14 relative to ccsm3.0?

To what extent has ccsm3.0.1 beta14 been tested?

In general, internal beta versions are not tested sufficiently for public release. Some internal beta versions undergo minimal testing. Often the scientific validity of a particular beta version is unknown. Many internal beta versions should not be used to produce science.

That said, ccsm3.0.1 beta14 has been tested more than most beta versions, in particular it has been verified that the default configuration of ccsm3.0.1 beta14, running on bluevista, lightning or pheonix, and running at the T31_gx3v5 resolution, will produce the same climate as the original ccsm3.0 release.

What is the distinction between a "public release" and an "internal beta version"?

A "public release" represents major milestones in CCSM code development. In a public release, both software functionality and scientific validity are extensively tested. Historically CCSM public releases have been created about every two years.

In support of a public release, numerous "internal beta versions" exist as part the CCSM software development process. Generally each beta version is subject to some testing, but this testing is no where near as extensive as for a public release. Often the scientific validity of a particular beta version is unknown. Some beta versions are known to result in bad science, a problem that will be corrected in some subsequent version. The use of an internal beta version to produce scientific results requires extra care and vigilance on the part of the user.