Direct ocean surface velocity measurements from space: Improved quantitative interpretation of Envisat ASAR observations

Type Publication
Date 2008-11
Language English
Copyright 2008 American Geophysical Union
Author(s) Johannessen J1, 2, Chapron Bertrand3, Collard F4, Kudryavtsev V1, 5, 6, Mouche Alexis4, Akimov D5, Dagestad K1
Affiliation(s) 1 : Nansen Environm & Remote Sensing Ctr, N-5006 Bergen, Norway.
2 : Univ Bergen, Inst Geophys, Bergen, Norway.
3 : Inst Francais Rech Exploitat Mer, F-29280 Plouzane, France.
4 : BOOST Technol, Brest, France.
5 : Nansen Int Environm & Remote Sensing Ctr, St Petersburg, Russia.
6 : Inst Marine Hydrophys, Sevastopol, Ukraine.
Source Geophysical Research Letters (0094-8276) (American Geophysical Union), 2008-11 , Vol. 35 , N. 22 , P. 1-6
DOI 10.1029/2008GL035709
WOS© Times Cited 45
Abstract Previous analysis of Advanced Synthetic Aperture Radar (ASAR) signals collected by ESA's Envisat has demonstrated a very valuable source of high-resolution information, namely, the line-of-sight velocity of the moving ocean surface. This velocity is estimated from a Doppler frequency shift, consistently extracted within the ASAR scenes. The Doppler shift results from the combined action of near surface wind on shorter waves, longer wave motion, wave breaking and surface current. Both kinematic and dynamic properties of the moving ocean surface roughness can therefore be derived from the ASAR observations. The observations are compared to simulations using a radar imaging model extended to include a Doppler shift module. The results are promising. Comparisons to coincident altimetry data suggest that regular account of this combined information would advance the use of SAR in quantitative studies of ocean currents. Citation: Johannessen, J. A., B. Chapron, F. Collard, V. Kudryavtsev, A. Mouche, D. Akimov, and K.-F. Dagestad (2008), Direct ocean surface velocity measurements from space: Improved quantitative interpretation of Envisat ASAR observations, Geophys. Res. Lett., 35, L22608, doi: 10.1029/2008GL035709.
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Johannessen J, Chapron Bertrand, Collard F, Kudryavtsev V, Mouche Alexis, Akimov D, Dagestad K (2008). Direct ocean surface velocity measurements from space: Improved quantitative interpretation of Envisat ASAR observations. Geophysical Research Letters, 35(22), 1-6. Publisher's official version : http://doi.org/10.1029/2008GL035709 , Open Access version : http://archimer.ifremer.fr/doc/00000/5168/