Linking hydrologic models and data: the OpenMI approach

Modeling frameworks provide the ability to create open, flexible modeling systems where simulations can be constructed from a set of computational modules interlinked for a given application. Various modeling frameworks have been proposed and developed with varying degrees of success. This paper investigates a more recent modeling framework, the Open Modeling Interface (OpenMI). OpenMI, which is freely available and open source (http://www.openmi.org), was developed by a consortium of public and private organizations in Europe. Various models are either already or in the process of becoming OpenMI compliant (e.g. MIKE-SHE, HEC-RAS, and Modflow). While using OpenMI to link existing models is one application of the framework, we are interested in determining the appropriateness of OpenMI as the underlying architecture for a community based hydrologic modeling system. We investigate this question by showing how the framework would allow a simulation model and database to be coupled, how OpenMI orchestrates the communication between these two components, and how OpenMI could be expanded to accommodate models and databases that are exposed as web services. We conclude with a discussion of the advantages and disadvantages of the OpenMI modeling framework and provide a vision for how a community model might be structured using an OpenMI-based approach