Cristin-resultat-ID: 1815993
Sist endret: 14. januar 2021, 12:22
NVI-rapporteringsår: 2020
Resultat
Vitenskapelig artikkel
2020

Evaluation of Radial Ocean Surface Currents Derived From Sentinel-1 IW Doppler Shift Using Coastal Radar and Lagrangian Surface Drifter Observations

Bidragsytere:
  • Artem Moiseev
  • Harald Johnsen
  • Morten Wergeland Hansen og
  • Johnny Andre Johannessen

Tidsskrift

Journal of Geophysical Research (JGR): Space Physics
ISSN 2169-9380
e-ISSN 2169-9402
NVI-nivå 2

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2020
Publisert online: 2020
Volum: 125:e2019JC015743
Hefte: 4
Sider: 1 - 18

Importkilder

Scopus-ID: 2-s2.0-85084011337

Beskrivelse Beskrivelse

Tittel

Evaluation of Radial Ocean Surface Currents Derived From Sentinel-1 IW Doppler Shift Using Coastal Radar and Lagrangian Surface Drifter Observations

Sammendrag

Ocean surface radial velocities (RVLs) derived from the Sentinel‐1 A/B Interferomic Wide (IW) mode Doppler frequency shift observations are regularly acquired over the Norwegian coastal zone. These data can be used to complement existing ocean observation systems with high‐resolution (up to 1.5 × 1.5 km) spatial ocean surface current (OSC) maps. In this study, Sentinel‐1 IW Level 2 OSC retrievals were obtained from 2 months (October–November 2017) of raw Doppler shift observations acquired over the Norwegian Coastal Current (NCC). The results were evaluated using coastal high‐frequency radar (HFR) and Lagrangian ocean surface drifter observations. The analysis shows that distinct patterns of the NCC, with range directed currents reaching up to 0.7 m/s, can be detected in the SAR data. The mean bias between Synthetic Aperture Radar (SAR) and HFR observations was −0.08 m/s and the root mean square deviation (RMSD) was 0.25 m/s. In comparison, the agreement between the SAR‐derived OSC and the trajectories from Lagrangian surface drifters showed a mean bias of 0.02 m/s and an RMSD of 0.24 m/s. The accuracy of the SAR OSC retrievals rely on precise wind‐wave bias correction. Hence, the accuracy of the model wind field (speed and direction) is crucial. The sea state contribution must also be taken into account during the bias correction. A typical required accuracy of the OSC velocity is on the order of 0.1 m/s. Therefore, the comparisons demonstrate that the use of SAR for OSC retrieval is promising.

Bidragsytere

Artem Moiseev

  • Tilknyttet:
    Forfatter
    ved Nansen Senter for Miljø og Fjernmåling

Harald Johnsen

  • Tilknyttet:
    Forfatter
    ved NORCE Energi og teknologi ved NORCE Norwegian Research Centre AS

Morten Wergeland Hansen

  • Tilknyttet:
    Forfatter
    ved Nansen Senter for Miljø og Fjernmåling
  • Tilknyttet:
    Forfatter
    ved Meteorologisk institutt

Johnny Andre Johannessen

  • Tilknyttet:
    Forfatter
    ved Geofysisk institutt ved Universitetet i Bergen
  • Tilknyttet:
    Forfatter
    ved Nansen Senter for Miljø og Fjernmåling
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