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Retrieval and Quality Assessment of Wind Velocity Vectors on the Ocean With C-Band SAR

Gisela Carvajal (Institutionen för rymd- och geovetenskap, Radarfjärranalys) ; Leif E.B. Eriksson (Institutionen för rymd- och geovetenskap, Radarfjärranalys) ; Lars M. H. Ulander (Institutionen för rymd- och geovetenskap, Radarfjärranalys)
IEEE Transactions on Geoscience and Remote Sensing (0196-2892). Vol. 52 (2014), 5, p. 2519-2537.
[Artikel, refereegranskad vetenskaplig]

Wind vector fields derived from synthetic aperture radar (SAR) sensors show variations at smaller scales than most other globally available surface wind sources. However, few studies have been devoted to the investigation of the accuracy of SAR-derived wind fields at different scales and how they compare with other wind data. In order to investigate these issues, an algorithm for the retrieval of SAR-derived wind vectors has been developed, and a quality assessment between the retrievals and in situ, scatterometer, and numerical weather model (NWM) wind data has been performed. The implemented wind retrieval algorithm detects streak features in the SAR image to estimate wind directions and inverts wind speeds using CMOD-IFR2, CMOD5, or CMOD5.N geophysical model functions. In addition, a regularization method for filtering outliers in the wind direction retrievals is used. Retrievals compared with in situ data indicated better performance at offshore locations for wind speed inversions with CMOD5.N. The bias and standard deviation for offshore regularized wind directions and CMOD5.N speeds are 9 degrees and 25 degrees and -0.1 and 1.4 m/s, respectively. The comparison with the scatterometer and NWM wind data has been performed for retrievals at 5-, 10-, and 20-km resolution. The results indicate a better agreement of the coarser retrievals with the reference data. Nevertheless, mapping of smaller scale features requires wind directions from the SAR image itself.

Nyckelord: Directional variation, numerical weather model (NWM), ocean surface wind, scatterometer, synthetic aperture radar (SAR), wind direction, wind direction variation with resolution, wind speed



Denna post skapades 2014-04-10. Senast ändrad 2016-06-30.
CPL Pubid: 196575

 

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Institutioner (Chalmers)

Institutionen för rymd- och geovetenskap, Radarfjärranalys

Ämnesområden

Geofysik

Chalmers infrastruktur