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-0226

Mesoscale Structure of Bio-Optical Properties Within the Northern
California Current System, 2000-2002

T J Cowles, J A Barth, C E Wingard, R A Desiderio, R M Letelier,
and S D Pierce

Mesoscale mapping of the hydrographic and bio-optical properties
of the Northern California Current System was conducted during
spring and summer 2000, 2001, and 2002 off the Oregon coast. A
towed, undulating vehicle carried a CTD, two fluorometers, a
multi-wavelength absorption and attenuation meter (ac-9), and a PAR
sensor. In addition, an ac-9 and a Fast Repetition Rate fluorometer
(FRRf) collected bio-optical data on surface waters throughout
the mesoscale surveys. Multiple onshore-offshore transect lines
provided repeated crossings of velocity jet and frontal boundaries,
and allowed resolution of physical and bio-optical parameters on
horizontal scales of 1km or less and on vertical scales of 1-2m. Our
multi-year results permit assessment of the linkages and the degree
of coupling between physical and bio-optical patterns during  strong
upwelling and strong downwelling events, as well as during low-wind
relaxation intervals. The location of the coastal jet and the
upwelling front fluctuated considerably under the variable forcing
regime, with more extensive mesoscale structure in all parameters
in late summer relative to spring, as current meanders developed
around subsurface topography (Heceta Bank) and moved offshore near
Cape Blanco. Sharp horizontal gradients in autotrophic biomass were
observed across the boundaries of the coastal jet and the upwelling
front, with chlorophyll levels often in excess of 5-10 mg m$^{-3}$
on the inshore side of the fronts. Horizontal gradients also
were observed in the spectral slope of attenuation and dissolved
absorption as well as in the physiological properties of the
autotrophic assemblages (as determined with FRRf).  Details of the
spatial correlations of physical and bio-optical parameters will
be presented.