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

OS61D-09

Progress on physical circulation and ecosystem modeling in the
COAST and WEST programs

J S Allen

High resolution physical circulation and ecosystem models have
been applied to study the mesoscale shelf flow field and ecosystem
response off Oregon and northern California in the regions of the
COAST and WEST field experiments.  Localized, regional domains
that extend approximately 400-600 km alongshore and 200-300 km
offshore are utilized to allow high horizontal grid resolutions of
1-2 km. The Princeton Ocean Model (POM) is used for Oregon while the
ROMS model is used for northern California. The Oregon ecosystem
model is a five component nitrogen-based NNPZD model. In the most
basic, workhorse configuration, periodicity conditions are used at
the alongshore boundaries, allowing the specification of well- posed
problems. For these shelf flows, where the mesoscale behavior is
dominated by the interaction of wind-driven currents with variable
shelf topography, that approximation leads to model results that
generally show good agreement with observations.  Open boundary
conditions have also been developed to allow the application of
spatially-variable forcing obtained from a high resolution mesoscale
atmospheric model. In addition, off Oregon a data assimilation system
utilizing HF-radar surface current measurements and a sequential
optimal interpolation scheme is being utilized to improve estimates
of the circulation. These models have been applied to the spring and
summer 2001 time periods of the COAST and WEST field experiments.
The modeled mesoscale shelf flow field off Oregon is strongly
influenced by interactions with Heceta Bank while the flow off
northern California is affected in a major way by Point Reyes. The
structure of model sea surface temperature fields reflects the shelf
flow interaction with these topographic features and is in good
qualitative agreement with comparable satellite-measured fields. New
information on the three-dimensional time-dependent nature of the
velocity, temperature, and turbulent kinetic energy fields, tested
with model/data comparisons where possible, is produced by the
model results. Examination of model dynamical balances has helped
provide rationalizations for the circulation processes responsible
for the structure of these fields. In particular, analyses of
model results have shown the prevalence and importance of pressure-
gradient-driven northward flows near the coast after the relaxation
of southward upwelling- favorable winds.  More detailed accounts
of the results from these modeling studies are reported at this
meeting by colleagues J. Gan, Y. Spitz, S. Couch and A. Kurapov.