Narragansett Bay Model
The Narragansett Bay Model uses the
Regional Ocean Modeling System (ROMS) on a domain which extends from
the Providence River in the north to the Rhode Island Sound interface in
the south. The open boundaries are forced with tidal heights and
amplitudes, as well as fresh water inputs from the Providence and other
rivers. At the surface, analytical wind stresses are imposed.
In the future, the model will include real wind data, multiple tracer
fields (biological and chemical), and source terms for runoff.
The model domain. Bathymetry has been smoothed using a Shapiro filter,
and smoothed to allow a minimum depth of 2m. All land cells are masked
out.
To calibrate the tidal velocities, three parameters are compared - vertical
mixing, horizontal mixing, and bottom roughness. Changing the bottom
roughness parameter strongly effects the 'double flood' velocity
field seen in the bay.
Summer work has involved releasing floats at the site of a mock oil
spill under various tidal, wind, and runoff conditions. These two
movies show the large effect that density driven flow has on the
outcome of particles released into the bay. Both cases in the
following movies are forced by a 5m/s constant wind from the south.
Constant density and no river mass flux.
Fresh water driven density gradient, small
mass flux from Providence RIver.
Our current project is working to look at residence times for subsections
of the bay using the same particle tracking scheme used in the oil spill
experiments.
Control case - no river flux, no wind.
River flux of 20 m^3/s, no wind.
More figures from model output.
This work is funded by Rhode Island Sea Grant.
Bridget Sullivan
Last modified: Thu Jan 10 17:20:01 EST 2002