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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 110,
C10S08,
doi:10.1029/2004JC002493,
2005
Assimilation of moored velocity data in a model of coastal wind-driven circulation off Oregon: Multivariate capabilities
Alexander L. Kurapov
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
J. S. Allen
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
G. D. Egbert
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
R. N. Miller
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
P. M. Kosro
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
M. D. Levine
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
T. Boyd
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
J. A. Barth
College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
Abstract
Horizontal current measurements from an array of moored acoustic Doppler profilers are assimilated sequentially into a model
of coastal wind-driven circulation off Oregon during the upwelling season of May–August 2001. Model results are compared against
independent moored and ship survey data to document a positive effect of velocity data assimilation (DA) on other oceanic
variables of interest such as the sea surface height (SSH), temperature, potential density, surface salinity, and near-bottom
turbulence parameters. Significant improvement is achieved for the nearshore SSH even when data are assimilated from only
two moorings at an alongshore distance of 50 km from the SSH verification site. At 45°N, in an area of simple shelf bathymetry
with relatively small alongshore variations, the model (even without DA) provides a good description of the isopycnal structure
on a cross-shore section. At 44.2°N, over complicated bathymetry, velocity DA may improve the slope of isopycnals but at the
same time not necessarily the density values themselves. Data assimilation based on a time-invariant representation of the
forecast error covariance may inhibit spatial variability on horizontal scales smaller than the assumed forecast error decorrelation
scale. An experiment involving assimilation of both velocity and moored salinity measurements demonstrates that moored velocity
DA improves transport of buoyant surface water. The level of improvement in the near-bottom turbulent dissipation and bottom
stress found with the DA model indicates that it is suitable for future studies of spatial and temporal variability in the
bottom boundary layer off Oregon.
Received 17
May
2004;
accepted 25
January
2005;
published 29
September
2005.
Keywords: shelf circulation;
modeling;
data assimilation.
Index Terms: 4217 Oceanography: General: Coastal processes; 4219 Oceanography: General: Continental shelf and slope processes (3002); 4255 Oceanography: General: Numerical modeling (0545, 0560); 4260 Oceanography: General: Ocean data assimilation and reanalysis (3225).
Read Full Article (file size: 1788479 bytes) Cited by
Citation: Kurapov, A. L., J. S. Allen, G. D. Egbert, R. N. Miller, P. M. Kosro, M. D. Levine, T. Boyd, and J. A. Barth
(2005),
Assimilation of moored velocity data in a model of coastal wind-driven circulation off Oregon: Multivariate capabilities,
J. Geophys. Res.,
110,
C10S08,
doi:10.1029/2004JC002493.
Copyright 2005 by the American Geophysical Union.
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