Retrieval of short ocean wave slope using polarimetric imaging

Publication Type  Journal Article
Year of Publication  2008
Authors  Zappa, C. J.; Banner, M. L.; Schultz, H.; Corrada-Emmanuel, A.; Wolff, L. B.; Yalcin, J.
Journal Title  Measurement Science & Technology
Volume  19
Issue  5
Pages  -
Journal Date  May
ISBN Number  0957-0233
Accession Number  ISI:000255662100021
Key Words  polarimetric imaging; sea surface roughness; wind waves; ocean wave slope; sea surface slope; capillary waves; gravity waves; wave breaking; wind-waves; water-waves; multiple images; number spectra; natural films; surface-waves; gas transfer; radiance; po

We present a passive optical remote sensing technique for recovering shape information about a water surface, in the form of a two-dimensional slope map. The method, known as polarimetric slope sensing (PSS), uses the relationship between surface orientation and the change in polarization of reflected light to infer the instantaneous two-dimensional slope across the field-of-view of an imaging polarimeter. For unpolarized skylight, the polarization orientation and degree of linear polarization of the reflected skylight provide sufficient information to determine the local surface slope vectors. A controlled laboratory experiment was carried out in a wave tank with mechanically generated gravity waves. A second study was performed from a pier on the Hudson River, near Lamont-Doherty Earth Observatory. We demonstrated that the two-dimensional slope field of short gravity waves could be recovered accurately without interfering with the fluid dynamics of the air or water, and water surface features appear remarkably realistic. The combined field and laboratory results demonstrate that the polarimetric camera gives a robust characterization of the fine-scale surface wave features that are intrinsic to wind-driven air-sea interaction processes.


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URL  <Go to ISI>://000255662100021
DOI  Doi 10.1088/0957-0233/19/5/055503