PRINCIPAL 

 INVESTIGATOR(S) 



Albert J. Williams 



Department of Applied Physics and Engineering 



Woods Hole Oceanographic Institution 



James H. Churchill 



Department of Physical Oceanography 

 Woods Hole Oceanographic Institution 

 Woods Hole, MA 02543 



PROJECT TITLE 



SEDIMENT MOTION AND BOTTOM BOUNDARY LAYER 

 DYNAMICS OVER THE MIDDLE ATLANTIC BIGHT SHELF 

 AND UPPER SLOPE 



AMOUNT OF FUNDING FY 1994: $229 K 



SUMMARY OF GOALS 



Our goal is to measure near bed sediment response to currents and waves on the shelf. 

 The flux of suspended sediment at various heights through the bottom boundary layer and the 

 total transport of particulates over the water column are the derived results. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



The measurements of velocity will be made from 50 cm above bottom to 5 m above 

 bottom at a depth of 20 meters to 120 meters across the shelf. We sample at 2Hz for several 

 months. Deployments can be 2 or 3 months long, limited by fouling of the optical turbidity 

 sensors. Our hope is to extend measurements of flux from the bottom to the surface, close 

 enough in height to obtain 80% coherence between adjacent measurements, perhaps 10 meters 

 apart in the midwater and closer at the bottom and top. Mooring should be close enough that 

 flux estimates are coherent to 80% between moorings. We estimate this to be 10 km in the mid- 

 shelf. 



METHODS AND PLATFORMS 



Optical backscatter measurements of turbidity will be correlated to instantaneous vector 

 velocities to obtain flux of particulates. This in turn will be integrated to yield transport. The 

 platform will be a mooring for the upper water column and a tripod for the bottom portion. 



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