Churchill, J. H. Woods Hole Oceanographic Institution, jchurchill@whoi.edu
Williams, A. H. Woods Hole Oceanographic Institution, awilliams@whoi.edu
Ralph, E. A. Large Lakes Observatory of the University of Minnesota, eralph@d.umn.edu

 
NEAR-BOTTOM SEDIMENT AND FLUID DYNAMICS IN THE COASTAL ZONE EAST OF LAKE SUPERIOR'S KEWEENAW PENINSULA.
 
The near-shore region west of Lake Superior's Keweenaw Peninsula is often host to a strong coastal flow known as the Keweenaw Current. To study near-bottom sediment and fluid dynamics within this region, we deployed two instrumented tripods at roughly the 27 m isobath and 4 km offshore of the Peninsula. One tripod was outfitted with arrays of acoustic travel time current meters, optical turbidity sensors, thermistors and fluorometers. The second supported an in-situ suspended particle sampler. Data from the current meter and thermistor arrays revealed frequent passages of the Keweenaw Current front. Instabilities of the front were revealed by rapid fluctuations of temperature and water velocity. Calculations suggest that these produced a significant exchange of water and suspended material across the front, with a net transport of suspended particles into the Current. The data also provided insight of near-bottom dynamics during atmospheric storms. Bottom stresses during storms were significantly enhanced by the action of surface wave currents, but to a lesser extent than typically observed within the coastal ocean during previous studies. Storm-generated stresses did not resuspend significant quantities of sediment at the study site, however, presumably owing to a scarcity of fine particles within bottom sediments.
 
Day: Thursday, Feb. 4
Time: 11:15 - 11:30am
Location: Eldorado Hotel
 
Code: SS52TH1115E