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Comparison of remotely measured and modelled currents in coastal areas of
Norway and Spain
H. H. ESSEN, Ø. BREIVIK, H. GÜNTHER,
K.-W. GURGEL, J. JOHANNESSEN, H. KLEIN, T. SCHLICK,
and M. STAWARZ
The Global Atmosphere and Ocean System (ISSN 1023-6732), Volume 9, Number 1-2,
pp. 38...64, 2003..
Abstract - -
Data from two six-week current measurement campaigns at the coasts of
Norway and Spain are presented. Spatial coverage of surface currents was
obtained by an HF (high frequency) radar. Subsurface currents were measured
by bottom-mounted and ship-borne ADCPs (acoustic doppler current profiler).
The HF data were assimilated by a fine gridded model with the aim of
predicting currents for about 6 h. The objective of this paper is twofold,
to investigate the performance of the instruments and the model, and to
show the high temporal and spatial variability of currents in the coastal
zones under investigation.
Several strong storms occured during the experiments with significant
waveheights exceeding 11 m (Norway) and 8 m (Spain), respectively.
High waves affected both the WERA (reduced ranges) and the ADCP (unreliable
near-surface current velocities). The assimilation algorithm of the model
worked well. The comparisons of measured and modelled maps of the
surface-current velocity, time series and horizontal gradients reveal
good agreement.
The analysis of current data shows similar features for both experimental
areas. The dominant M2-tidal currents are weak (amplitudes of about
0.15 m/s). The spatial distribution of the vector correlation between
surface current and wind is homogeneous, although single current maps
contain strong horizontal variabilities. The portion of current variance
linearly forced by wind is about 30 %.
Keywords - -
coastal zone, ocean currents, HF radar, ADCP, fine-gridded model
gurgel@ifm.uni-hamburg.de
Last update: Friday, 18-May-2007 14:44:45 CEST
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