We propose to investigate the feasibility and value of the "Software as a Service" paradigm in facilitating access to Earth Science numerical models. We envision providing prototype Web-based access to NASA scientific models (GEOS-5, WRF) and their results, via industry-standard service interfaces (OGC's Web Coverage Service, Web Map Service, OPeNDAP) implemented by open-source software tools such as MapServer and THREDDS. These services would allow declarative access to pre-computed model outputs, on-demand (asynchronous or synchronous) model runs, and user-customizable model workflows. These services would use the MAP Mobile Environment Workflow tool and associated templates to encapsulate details of the model software and the computing environment in which it runs. Providing these modeling capabilities as a service, through well-defined, widely-supported Web interfaces, would facilitate loosely-coupled collaborative work among different computing facilities and different disciplines; and it would broaden access to modeling beyond those already "in the know" or qualified to login to a NASA computing resource. We will conduct the study in stages, beginning with Web access to pre-stored model results, followed by on-demand model runs and culminating in service-based workflow customization.
