Fall AGU Meeting (Dec. 2002) COAST abstracts:

• Allen
  
• Bane et al.
  
• Barth et al.
  
• Carney et al.
  
• Couch et al.
  
• Cowles et al.
  
• Dale et al.
  
• Durski et al.
  
• Egbert et al.
  
• Gan et al.
  
• Hales et al.
  
• Kosro et al.
  
• Kuebel et al.
  
• Kurapov et al.
  
• Perlin et al.
  
• Pierce et al.
  
• Ruttenberg et al.
  
• Samelson
  
• Spitz et al.
  
• Wheeler
  

Abstracts should be cited as:

EOS Trans. AGU, 83 (47),
Fall Meet. Suppl.,
Abstract XXXXX-XX, 2002

OS62A-0227

Dye tracer studies of wind-driven upwelling on the Oregon shelf

A C Dale, J A Austin, J A Barth, and M Levine

A series of dye releases from a small boat during the summers
of 2001/2002 has investigated cross-shelf circulation in a region
dominated by intermittent wind-driven upwelling. The aim was to make
direct, Lagrangian observations of the pathways of cross-shelf flow
during active upwelling. Lagrangian techniques provide insight that
is not available from Eulerian measurements because of the dominance
of alongshelf flow. Preliminary results will be reported, with
emphasis on a release from August 2002, made as winds transitioned
from weakly downwelling-favorable to weakly upwelling-favorable. Dye
was seeded in an alongshore streak at 20m depth in 55m of water,
a little beneath the pycnocline. Of note was the rapid onshore
spreading of the dye patch, having a cross-shelf extent of 5km after
48 hours, and extending into shallow water (less than 20m bottom
depth). The dye remained largely isopycnal, following the upper edge
of the bottom boundary layer onshore. The offshore edge of the patch
became associated with a strong temperature inversion - a warm layer,
apparently composed of subducted near-surface water. This dataset
will provide an opportunity to determine the source of water in such
inversions and to evaluate potential mechanisms for their formation.