Headland Eddy Formation and Dissipation
at Three Tree Point, Washington
Funded by the National Science Foundation (PI's: P. MacCready, G. Pawlak)
The objective of the study is to observe the formation and dissipation of a headland eddy in deep water. Included in this is examination of the vertical structure of vorticity within an eddy and of the baroclinic response of the flow around the sloping headland. The selected site for the observations is Three Tree Point in Puget Sound, WA. The third set of observations was carried out between June 7 through June 16, 2002 using the UW R/V Clifford A. Barnes and the UW/APL R/V C. E. Miller.
Tidal currents and cruise schedule
ADCP/CTD Scheme
Animation of drifter tracks from June 2002 Cruise
(click on left image for an .avi sequence - 1.4 MB)
Satellite-tracked drifters released around Three Tree Point show the formation of an eddy on the lee side of the headland during the flood tides on June 7-15, 2002. The tracks represent accumulated drifter data from nine separate deployments of ten drifters. Separate deployments are coded by color. The animation shows the progression of the eddy on the following tidal cycles revealing a long-lived flow structure that persists through the following tidal cycle.
Phase aligned ship-ADCP survey results (from 7 different days) near max flood from June 2002. The left panel shows raw velocity vectors at 20 m for one hour centered on 1/2 hour after max flood. The right panel shows the objectively analyzed gridded vector field, and the relative vorticity (color). The flood eddy is apparent, as is a tail of high vorticity leading to the separation point.
G. Pawlak (UH Ocean Engineering)
P. MacCready (UW Oceanography)
K. Edwards (UW Oceanography)
R. McCabe (UW
Oceanography)
Return to Three Tree Point page
for more info contact:
Geno Pawlak or Parker MacCready
last modified: 02/26/2004