sheremet november 18-20, 2003u.s. globec georges bank multiple flow pathways of the scotian shelf...

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Multiple Flow Pathways of the Scotian Shelf Water onto Georges Bank

V. Sheremet, Y.-K. Cho,

R. Beardsley

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Topography and Circulation

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

16 February 1999 crossover

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

5 March 1997 crossover

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Mooring records

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Drifters

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Important Factors

• Freshwater pulses from the Gulf of St. Lawrence

• Along-shelf flow in the shelf/slope front

• Instability of the SSW front around Browns Bank

• Synoptic wind events

• Warm-core rings

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Williams et al. 2001

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Numerical modeling

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Bathymetry

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Abrupt changes: 1.5 C

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Kuroshio

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Lab Experiment

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Onset of Flow Separation

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Particle Image Velocimetry

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Importance of Bottom Drag

• Advective time scale

• Scotian Shelf, Strong tidal dissipation

• Laboratory

November 18-20, 2003 U.S. GLOBEC Georges Bank Sheremet

Conclusions

• Numerical experiments suggest that the system is close to a bimodal state

• Baroclinicity and friction relax potential vorticity constraint and allow the crossover

• Inertia promotes the crossovers and along with baroclinicity affects the position of flow separation

• Tidally modulated bottom drag, especially during winter unstratified conditions