Mid- and far-infrared measurements of sun glint from the sea surface

Alfred W. Cooper; Eugene C. Crittenden Jr.; Edmund A. Milne; Philip L. Walker; E. Moss; Dennis J. Gregoris

doi:10.1117/12.138846

22 December 1992 Mid- and far-infrared measurements of sun glint from the sea surface

Alfred W. Cooper, Eugene C. Crittenden Jr., Edmund A. Milne, Philip L. Walker, E. Moss, Dennis J. Gregoris

Proceedings Volume 1749, Optics of the Air-Sea Interface: Theory and Measurement; (1992) https://doi.org/10.1117/12.138846
Event: San Diego '92, 1992, San Diego, CA, United States

Abstract

Measurements are reported of the infrared sunglint clutter channel caused by the direct solar reflection from the wave-perturbed sea surface at near-grazing angles of incidence. Apparent radiance has been measured over Monterey Bay as a function of azimuth and elevation angles relative to the sun direction using an AGA Thermovision 780 dual-band radiometric imaging system in the wavebands 2 to 5.6 (SW) and 8 to 12 micrometers (LW) with 7 degree(s) FOV. Time averaged profiles from multiframe averages show near-Gaussian angular distributions with half widths in the range 3 to 20 degrees (depending on solar angle) for look-down angles of 1 to 10 degrees below the horizon. The p- and s- polarized components of sea surface radiance have been obtained using an external wire-grid polarizing filter and compared with unpolarized measurements. The degree of polarization within the glint is shown to be horizontal and variable in the range 1% to 30%, depending on solar elevation, the higher degrees of polarization being found in the SW band. Significant vertical sea radiance polarization has been observed outside the solar glint in the 8 to 12 micrometers band, and is attributed to sea surface emission polarization.

Citation Download Citation

Alfred W. Cooper, Eugene C. Crittenden Jr., Edmund A. Milne, Philip L. Walker, E. Moss, and Dennis J. Gregoris "Mid- and far-infrared measurements of sun glint from the sea surface", Proc. SPIE 1749, Optics of the Air-Sea Interface: Theory and Measurement, (22 December 1992); https://doi.org/10.1117/12.138846

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