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Wind rolls in the Atlantic Ocean
 The
wind direction can be estimated in SAR images by examination of the low spatial
frequency in the image spectrum. As the presence of rolls in the atmospheric
boundary layer can cause streaks to appear in the SAR images, the direction
of these can be used to estimate the wind direction with an ambiguity of 180º.
This figure shows a
low-frequency wavenumber spectrum derived from the SAR image from 10 November
1991. The energy in the spectrum is concentrated in a SW-NE direction, and this
will be perpendicular to the streaks, and hence wind direction.
Taking into account the azimuth angle, the derived wind direction (with the
180º ambiguity) is shown in this
figure.
An in situ measurement (approximately 20 km SW of image center) of the wind
direction is indicated to the right.
NERSC, Bergen, Norway
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,
atmospheric chemistry
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EO Data Access
The
wind direction can be estimated in SAR images by examination of the low spatial
frequency in the image spectrum. As the presence of rolls in the atmospheric
boundary layer can cause streaks to appear in the SAR images, the direction
of these can be used to estimate the wind direction with an ambiguity of 180º.
