The Regional Ocean Modeling System (ROMS) results shown here are for a prototype "LaTTE" model covering a portion of the mid-Atlantic Bight from the center of Long Island to south of the mouth of the Delaware.
Model results are plotted at 12-hourly intervals, and show salinity or temperature at 5m depth with velocity vectors. Surface wind stress is also plotted.
Salinity at 5m:
http://marine.rutgers.edu/~wilkin/wip/latte/salt
Temperature at 5m:
http://marine.rutgers.edu/~wilkin/wip/latte/temp
ROMS LaTTE configuration
The model horizontal resolution is approximately 1 km with 30 vertical levels. The domain is limited to the continental shelf. The model bathymetry was taken from the 15 arc second (~460 m) data of the NGDC Coastal Relief Model. The maximum depth is 100 m at the end of the Hudson Canyon. Most of the domain has depths shallower than 60 m.
Initial conditions are from a simple climatological (nominally at April 16) average of historic hydrographic observations computed by weighted least squares regression following isobaths. The hydro data used were a combination of stations in the NOAA/NMFS archive provided by Maureen Taylor of NMFS Woods Hole, data in the NODC archive, and other observations by the Rutgers University Long-term Ecosystem Observatory (LEO) programs.
Open boundary conditions are simple Orlanski-type radiation augmented with tidal harmonic forcing taken from an ADCIRC model of the western Atlantic (Luettich et al. 1992). Following 8-days of spin-up with meteorological and hydrologic focing, the tides were activated on April 25. The weak mean southward flow of the mid-Atlantic Bight inner shelf is not imposed in the boundary conditions.
Air-sea heat and momentum fluxes are calculated by the bulk formulae of Fairall et al. (1996) using the model sea surface temperature and sea level air temperature, pressure, relative humidity, and 10-meter winds from the National Weather Service ETA model (at 12-km resolution). Long-wave radiation is computed by the Berliand approximation. Short-wave radiation is a simple cloud-free value.
The inflow of the Hudson River is specified using a simple estimate computed as 1.3 times the sum of the daily mean observations at the Mohawk and Fort Edward USGS gauges. The other rivers entering the domain (Delaware River, Raritan River, Wading River and Toms River) are specified as monthly climatological values.
Background:
ROMS is a free surface primitive equations ocean model being used by a rapidly growing user community for applications from the basin to coastal and estuarine scales (e.g. Haidvogel et al. 2000, Marchesiello et al. 2003, MacCready and Geyer 2001). Model features are summarized briefly in Table 1 and the computational algorithms are described in detail by Shchepetkin and McWilliams (1998; 2003a, 2003b). Careful formulation of the time-stepping algorithm allows both exact conservation and constancy preservation for tracers, while achieving enhanced stability and accuracy in coastal applications where the free surface displacement is a significant fraction of the total water depth. Conservative parabolic-spline discretization in the vertical has greatly reduced the pressure-gradient truncation error that has plagued previous terrain-following coordinates models.
| Table 1: ROMS model features | |
| - free
surface, hydrostatic primitive equations model in terrain-following coordinates
- 3rd-order upstream-biased advection (Shchepetkin and McWilliams, 1998) - pressure gradient and equation of state give reduced s-coordinate truncation error (Shchepetkin and McWilliams, 2003a) - split-explicit time-stepping of barotropic and baroclinic modes constrained for conservation of volume and tracer constancy (Shchepetkin and McWilliams 2003b) - radiation open boundary conditions and 1-way embedding in exterior model domains (Marchesiello et al. 2001) |
- synchronous
Lagrangian particle tracking - vertical turbulence closures: KPP (Large et al. 1994) and the Generalized Length Scale scheme of Umlauf, and Burchard, 2003 (http://www.gotm.net) encompassing k-e, k-w and Mellor-Yamada (1982) - intermittent sub-optimal melding assimilation - tangent linear and adjoint codes written; 4DVar assimilation in development (Moore et al. 2003) - atmospheric, oceanic, and benthic (wave and current) boundary layers (Styles and Glenn) - coupled ecosystem (7-component NPZD and EcoSim bio-optics) and sediment transport (USGS Community Model) modules |
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