Coupling integrated Earth System Model components with BFG2

GENIE is a suite of modular Earth System Model components coupled in a variety of configurations used to investigate climate phenomena. As part of the GENIEfy project, there is a desire to make the activity of coupling GENIE configurations more flexible in order to ease the integration of new components, permit experimentation with alternative model orderings and connectivity, and execute GENIE components in distributed environments. The current coupling framework is inflexible because models are run in a fixed order by a prescriptive main code. This paper shows how the BFG2 (Bespoke Framework Generator-version 2) coupling tool offers significantly more flexibility. Using BFG2, scientists describe GENIE configurations as metadata that can then be transformed automatically into the desired framework. It is demonstrated that BFG2 provides flexibility in composition and deployment, improvements that are brought without modification to the GENIE components, without loss of performance and in a such a manner that it is possible to produce exactly the same results as under the original framework. We also demonstrate how BFG2 may be used to improve the performance of future GENIE coupled models. Copyright (C) 2008 John Wiley & Sons, Ltd.