CSDMS 2011 annual meeting poster Carl Friedrichs
Results of the US IOOS Testbed for Comparison of Hydrodynamic Models of the Chesapeake Bay
Aaron Bever, VIMS , USA.
Marjorie Friedrichs, VIMS , USA.
Malcolm Scully, ODU , USA.
Estuarine Hypoxia Testbed Team , , USA.
Through funding provided by the US Integrated Ocean Observing System, five open source 3-D hydrodynamic models for Chesapeake Bay have been compared to each other and to EPA monitoring data for hindcasts of the years 2004 and 2005. The aim of this project is to provide NOAA, EPA, other government agencies, and the larger modeling community meaningful guidance on the relative accuracy, efficiency, complexity and likely utility for federal operational and scenario modeling of a suite of community models available for simulating hydrodynamics and oxygen dynamics in Chesapeake Bay. The focus of the present paper is on the hydrodynamic comparison of:
- the ChesROMS model (http://ches.communitymodeling.org/models/ChesROMS/index.php)
- the CBOFS2 model (http://cedb.asce.org/cgi/WWWdisplay.cgi?265616)
- the CH3D model (http://www.chesapeakebay.net/publication.aspx?publicationid=55318)
- the EFDC model
- the UMCES ROMS model
These models represent a range of resolutions (from ~5,000 to ~50,000 wetted cells). The models do similarly well in reproducing 3-D, time-dependent temperature fields. Bottom salinity is significantly improved with increases in horizontal resolution that better capture the structure of narrow, deep channels. Seasonal variation in density stratification is surprisingly difficult for all the models to capture well, and density stratification is not found to be especially sensitive to horizontal or vertical resolution within the range of resolutions considered. The hydrodynamics in general are not particularly sensitive to refinements in offshore climatological forcing, nor to refinements in riverine input, nor to refinements in spatial resolution of wind forcing. Lateral and longitudinal advection is sensitive, however, to seasonal changes in wind velocity and direction, suggesting that typical seasonal changes in wind forcing may be more important than seasonal changes in local stratification in controlling transfer of oxygen to deep channels susceptible to hypoxia.
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