Doppio – A ROMS-based Circulation Model for the Mid-Atlantic Bight and Gulf of Maine: Configuration and comparison to integrated coastal observing network observations

Abstract. We describe Doppio , a ROMS-based model of the Mid-Atlantic Bight and Gulf of Maine regions of the northwest North Atlantic developed in anticipation of future applications to biogeochemical cycling, ecosystems, estuarine downscaling, and near-real-time forecasting. This free-running regional model is introduced with circulation simulations covering 2007–2017. The ROMS configuration choices for the model are detailed, and the forcing and boundary data choices described and explained. A comprehensive observational data set is compiled for skill assessment from satellites and in situ observations from Regional Associations of the U.S. Integrated Ocean Observing Systems, including moorings, autonomous gliders, profiling floats, surface current measuring coastal radar, and fishing fleet sensors. Doppio's performance is evaluated with respect to these observations by representation of sub-regional temperature and salinity error statistics, as well as velocity and sea level coherence spectra. Model circulation for the Mid-Atlantic Bight and Gulf of Maine is visualized alongside the mean dynamic topography to convey the model's capabilities.