Polarization of 'water-skies' above arctic open waters: how polynyas in the ice-cover can be visually detected from a distance

J Opt Soc Am A Opt Image Sci Vis. 2007 Jan;24(1):132-8. doi: 10.1364/josaa.24.000132.


The foggy sky above a white ice-cover and a dark water surface (permanent polynya or temporary lead) is white and dark gray, phenomena called the 'ice-sky' and the 'water-sky,' respectively. Captains of icebreaker ships used to search for not-directly-visible open waters remotely on the basis of the water sky. Animals depending on open waters in the Arctic region may also detect not-directly-visible waters from a distance by means of the water sky. Since the polarization of ice-skies and water-skies has not, to our knowledge, been studied before, we measured the polarization patterns of water-skies above polynyas in the arctic ice-cover during the Beringia 2005 Swedish polar research expedition to the North Pole region. We show that there are statistically significant differences in the angle of polarization between the water-sky and the ice-sky. This polarization phenomenon could help biological and man-made sensors to detect open waters not directly visible from a distance. However, the threshold of polarization-based detection would be rather low, because the degree of linear polarization of light radiated by water-skies and ice-skies is not higher than 10%.

Publication types

  • Evaluation Study

MeSH terms

  • Algorithms*
  • Arctic Regions
  • Computer Simulation
  • Environmental Monitoring / methods*
  • Ice Cover / chemistry*
  • Image Enhancement / methods*
  • Image Interpretation, Computer-Assisted / methods*
  • Information Storage and Retrieval / methods*
  • Models, Statistical
  • Oceans and Seas
  • Refractometry / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity