Circulation and mixing at the New England shelfbreak front: Results of purposeful tracer experiments

Publication Status is "Submitted" Or "In Press: 
LDEO Publication: 
Publication Type: 
Year of Publication: 
2006
Editor: 
Journal Title: 
Progress in Oceanography
Journal Date: 
Place Published: 
Tertiary Title: 
Volume: 
70
Issue: 
2-4
Pages: 
289-312
Section / Start page: 
Publisher: 
ISBN Number: 
0079-6611
ISSN Number: 
Edition: 
Short Title: 
Accession Number: 
ISI:000241170000012
LDEO Publication Number: 
Call Number: 
Abstract: 

We present the results of six dye tracer experiments that measured the mixing and circulation at the shelfbreak front on the New England Shelf. The last three were conducted during the New England Shelfbreak Productivity Experiment (NESPEX) with concurrent isopycnal float deployments. The results are consistent with the Chapman and Lentz [Chapman, D.C., and Lentz, S.J. (1994). Trapping of a coastal density front by the bottom boundary layer. Journal of Physical Oceanography, 24, 1465-1479.] model prediction of the separation and upwelling along the shelfbreak front of bottom boundary layer (BBL) water forced by an Ekman buoyancy flux, but show considerable variability. Cross-shelf velocities at the detachment point are 2-3 x 10(-2) m/s. But seaward, over the slope region, dye tagged water was sheared from the main patch into small filaments that upwelled along the front with cross-shelf speeds up to 0.1 m/s. Cross-shelf diffusion was of order 10 m(2)/s in the mixed bottom layer and 1 m(2)/s in the interior along the front. Within the stratified front, the mean vertical diffusivity was K-z similar to 4 x 10(-6) m(2)/s. The dispersion of shelfwater in the slope region is effected by turbulent flow with advective speeds exceeding the small scale diffusive mixing. The mean flux of the detached BBL water is sufficient to account for the net loss of shelf water during its transit from Cape Cod to Cape Hatteras. (C) 2006 Elsevier Ltd. All rights reserved.

Notes: 

093LOTimes Cited:0Cited References Count:26

DOI: 
DOI 10.1016/j.pocean.2006.05.001