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Imaging polarimetry of the fogbow: polarization characteristics of white rainbows measured in the high Arctic

Horvath, Gabor; Hegedues, Ramon; Barta, Andras; Farkas, Alexandra and Åkesson, Susanne LU (2011) In Applied Optics 50(28). p.64-71
Abstract
The knowledge on the optics of fogbows is scarce, and their polarization characteristics have never been measured to our knowledge. To fill this gap we measured the polarization features of 16 fogbows during the Beringia 2005 Arctic polar research expedition by imaging polarimetry in the red, green and blue spectral ranges. We present here the first polarization patterns of the fogbow. In the patterns of the degree of linear polarization alpha fogbows and their supernumerary bows are best visible in the red spectral range due to the least dilution of fogbow light by light scattered in air. In the patterns of the angle of polarization alpha fogbows are practically not discernible because their alpha-pattern is the same as that of the sky:... (More)
The knowledge on the optics of fogbows is scarce, and their polarization characteristics have never been measured to our knowledge. To fill this gap we measured the polarization features of 16 fogbows during the Beringia 2005 Arctic polar research expedition by imaging polarimetry in the red, green and blue spectral ranges. We present here the first polarization patterns of the fogbow. In the patterns of the degree of linear polarization alpha fogbows and their supernumerary bows are best visible in the red spectral range due to the least dilution of fogbow light by light scattered in air. In the patterns of the angle of polarization alpha fogbows are practically not discernible because their alpha-pattern is the same as that of the sky: the direction of polarization is perpendicular to the plane of scattering and is parallel to the arc of the bow, independently of the wavelength. Fogbows and their supernumeraries were best seen in the patterns of the polarized radiance. In these patterns the angular distance delta between the peaks of the primary and the first supernumerary and the angular width sigma of the primary bow were determined along different radii from the center of the bow. delta ranged between 6.08 degrees and 13.41 degrees, while sigma changed from 5.25 degrees to 19.47 degrees. Certain fogbows were relatively homogeneous, meaning small variations of delta and sigma along their bows. Other fogbows were heterogeneous, possessing quite variable delta- and sigma-values along their bows. This variability could be a consequence of the characteristics of the high Arctic with open waters within the ice shield resulting in the spatiotemporal change of the droplet size within the fog. (C) 2011 Optical Society of America (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Optics
volume
50
issue
28
pages
64 - 71
publisher
OSA
external identifiers
  • wos:000295842600009
  • scopus:80053400409
ISSN
2155-3165
language
English
LU publication?
yes
id
bf28bf03-b76d-4ee9-a4d7-8b3e35cc5883 (old id 2211612)
date added to LUP
2011-11-25 13:48:27
date last changed
2017-10-22 03:19:53
@article{bf28bf03-b76d-4ee9-a4d7-8b3e35cc5883,
  abstract     = {The knowledge on the optics of fogbows is scarce, and their polarization characteristics have never been measured to our knowledge. To fill this gap we measured the polarization features of 16 fogbows during the Beringia 2005 Arctic polar research expedition by imaging polarimetry in the red, green and blue spectral ranges. We present here the first polarization patterns of the fogbow. In the patterns of the degree of linear polarization alpha fogbows and their supernumerary bows are best visible in the red spectral range due to the least dilution of fogbow light by light scattered in air. In the patterns of the angle of polarization alpha fogbows are practically not discernible because their alpha-pattern is the same as that of the sky: the direction of polarization is perpendicular to the plane of scattering and is parallel to the arc of the bow, independently of the wavelength. Fogbows and their supernumeraries were best seen in the patterns of the polarized radiance. In these patterns the angular distance delta between the peaks of the primary and the first supernumerary and the angular width sigma of the primary bow were determined along different radii from the center of the bow. delta ranged between 6.08 degrees and 13.41 degrees, while sigma changed from 5.25 degrees to 19.47 degrees. Certain fogbows were relatively homogeneous, meaning small variations of delta and sigma along their bows. Other fogbows were heterogeneous, possessing quite variable delta- and sigma-values along their bows. This variability could be a consequence of the characteristics of the high Arctic with open waters within the ice shield resulting in the spatiotemporal change of the droplet size within the fog. (C) 2011 Optical Society of America},
  author       = {Horvath, Gabor and Hegedues, Ramon and Barta, Andras and Farkas, Alexandra and Åkesson, Susanne},
  issn         = {2155-3165},
  language     = {eng},
  number       = {28},
  pages        = {64--71},
  publisher    = {OSA},
  series       = {Applied Optics},
  title        = {Imaging polarimetry of the fogbow: polarization characteristics of white rainbows measured in the high Arctic},
  volume       = {50},
  year         = {2011},
}