High-Resolution Wind Fields from SAR Imagery
With satellite SAR imagery, ocean wind fields in coastal regions can be estimated with a resolution of a few hundred meters to a few kilometers. Wind retrieval from SAR is typically limited to wind speed ranging from 3-18m/s. In some cases the retrieval can be complicated due to presence of atmospheric gravity waves.
Example 1: ERS-1 SAR 22 June 1996
This image over a part of the Norwegian coast Northwest of the city of Bergen shows several atmospheric related linear features (a-b). The typical wind directions in this area are southerly and northerly along the coast. On the present day the wind is 14.7m/s from 349° reported at the lighthouse weather station in the area. Wakes and gap winds are seen in the mouth of Sognefjord (c). For a site in mid- and northern-Europe such as this, the wind field product can be generated on average every 3 days. The original SAR image is here.
Wind field derived from ERS-1 SAR, 22 June 1996. © 2003 NERSC |
Sub-images:
More examples:
Algorithm:
The CMOD-IFR2 algorithm is used to estimate wind from SAR images. Other algorithms used for wind retrieval from satellite radar imagery include the CMOD-4 and the ENVIWAVE algorithm.