transparent gif


Ej inloggad.

Göteborgs universitets publikationer

Comparison of HF radar measurements with Eulerian and Lagrangian surface currents

Författare och institution:
J. Rohrs (-); A. K. Sperrevik (-); K. H. Christensen (-); Göran Broström (Institutionen för geovetenskaper); O. Breivik (-)
Publicerad i:
Ocean Dynamics, 65 ( 5 ) s. 679-690
Artikel, refereegranskad vetenskaplig
Sammanfattning (abstract):
High-frequency (HF) radar-derived ocean currents are compared with in situ measurements to conclude if the radar observations include effects of surface waves that are of second order in the wave amplitude. Eulerian current measurements from a high-resolution acoustic Doppler current profiler and Lagrangian measurements from surface drifters are used as references. Directional wave spectra are obtained from a combination of pressure sensor data and a wave model. Our analysis shows that the wave-induced Stokes drift is not included in the HF radar-derived currents, that is, HF radars measure the Eulerian current. A disputed nonlinear correction to the phase velocity of surface gravity waves, which may affect HF radar signals, has a magnitude of about half the Stokes drift at the surface. In our case, this contribution by nonlinear dispersion would be smaller than the accuracy of the HF radar currents, hence no conclusion can be made. Finally, the analysis confirms that the HF radar data represent an exponentially weighted vertical average where the decay scale is proportional to the wavelength of the transmitted signal.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Geovetenskap och miljövetenskap ->
Oceanografi, hydrologi, vattenresurser ->
HF radar, Stokes drift, Surface current, Surface drifter, WAVES, ASSIMILATION, WATER, Oceanography
Postens nummer:
Posten skapad:
2015-05-12 11:19

Visa i Endnote-format

Göteborgs universitet • Tel. 031-786 0000
© Göteborgs universitet 2007