Bogden, P. S. University of Connecticut, Marine Sciences, philip@oceans.dms.uconn.edu
O'Donnell, J. S. University of Connecticut, Marine Sciences, odonnell@uconnvm.uconn.edu

 
ESTIMATING THE CIRCULATION IN EASTERN LONG ISLAND SOUND WITH AN INVERSE MODEL AND A SHIPBOARD ADCP: DOES IT WORK?
 
In the summer of 1997, three weeks of 10-hour surveys were conducted in eastern Long Island Sound. The objective was to test the ability to distinguish tidal and non-tidal flow with a shipboard ADCP. In particular, Bogden and O'Donnell (1998, J. Mar. Res. 56: 989-1022) found that data from a single survey could be used to improve a tidal model for several days in central Long Island Sound, where tidal flows are relatively weak. They also showed that removing the improved tidal currents from the ADCP data revealed periods of weak but statistically significant residual depth-averaged circulation. Our objective with the 1997 sea-going program was to provide a data set with sufficient time and space resolution to test earlier results. In addition to having stronger tidal currents, prognostic models predict that eastern Long Island Sound has substantially stronger barotropic residual flow (Rich Signell, U.S.G.S., personal communication). The inverse model provides data-dependent adjustments to the prior tidal model. The prior is a standard linear barotropic shallow water model. Preliminary results from the inverse show that the accuracy of adjustments is sensitive to assumptions about the dynamical error statistics (i.e., assumptions about how much model adjustment is reasonable). A prognostic model with more accurate nonlinear physics is used to provide bounds on the inverse model adjustments. Results address the question asked in the title.
 
Day: Friday, Feb. 5
Time: 11:15 - 11:30am
Location: Eldorado Hotel
 
Code: CS57FR1115E