Wednesday, June 24, 2009

So You Want to Model: Part 1

This post is part 1 of a two part response to a comment on a post concerning numerical modeling of the space environment. TelepathicTroy called for Open Source space codes in order to develop transparency as far as code capability and performance.

This post presents a non-open source solution to this issue: The Community Coordinated Modeling Center. The CCMC is a NASA-run organization that acts as a third party who runs and compares many different space weather models. Furthermore, they provide a resource to the community for running these models and visualizing their results. Although this is not opening up source code to everyone, it does give non-code developers the chance to run each model through a gauntlet of tests and evaluations.

This resource is open to everyone. Check out their runs on request section, or browse their library of simulation results and play with their plotting tools. There are results available from recent model comparisons, the conclusions of which were presented at the current GEM Workshop.

There are issues, however. A limited set of parameters and controls for each model are available to the end user, and this leads to model developers contesting CCMC results that may show their model in a bad light. It is constantly asserted by developers that the results of a certain run would be much more favorable if CCMC had used a certain set of paramters instead of their defaults (typically picked for robustness.) I must admit guilt to this very charge, but in some cases the developer is indeed correct. So while the CCMC is a powerful comparison and evaulation tool, it is still cannot do what an open source approach can: provide 100% transparency to what a code is doing and how well it does it.

It is interesting that such a tool could give rise to a hobby-based or grass roots space weather modeling crowd. Unlikely, but an intriguing prospect.

Stay tuned for Part 2: the SWMF.

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