Evaluation of Model Coupling Frameworks for Use by the Community Surface Dynamics Modeling System (CSDMS)

The Community Surface Dynamics Modeling System (CSDMS) is a recently NSF-funded project that represents an effort to bring together a diverse community of surface dynamics modelers and model users. Key goals of the CSDMS project are to (1) promote open-source code sharing and re-use, (2) to develop a review process for code contributions, (3) promote recognition of contributors, (4) develop a "library" of low-level software tools and higher-level models that can be linked as easily as possible into new applications and (5) provide resources to simplify the efforts of surface dynamics modelers. The architectural framework of CSDMS is being designed to allow code contributions to be in any of several different programming languages (language independence), to support a migration towards parallel computation and to support multiple operating systems (platform independence). In addition, the architecture should permit structured, unstructured and adaptive grids. A variety of different "coupling frameworks" are currently in use or under development in support of similar projects in other communities. One of these, ESMF (Earth System Modeling Framework), is primarily centered on Fortran90, structured grids and Unix-based platforms. ESMF has significant buy-in from the climate modeling community in the U.S.; a closely-related framework called OASIS4 has been adopted by many climate modelers in Europe. OpenMI has emerged from the hydrologic community in Europe and is likely to be adopted for the NSF-funded CUAHSI project. OpenMI is primarily centered on the Windows platform and a programming language called "C-sharp" and is not oriented toward parallel computing. A third, DOE-funded framework called CCA (Common Component Architecture) achieves language interoperability using a tool called Babel. It fully supports parallel computation and virtually any operating system. CCA has also been shown to be interoperable with ESMF and MCT (Model Coupling Toolkit) and would appear to be interoperable with OpenMI if C-sharp language support were to be added to Babel. For all of these reasons CCA is very attractive as a base framework for the CSDMS project. This poster will present a comparison of several different coupling frameworks and will provide a demonstration of how component-based software can be developed within the CCA framework.