| Résumé | We report results of a two-year campaign of measurements, during arctic winter darkness, of optical turbulence in the atmospheric boundary layer above the Polar Environment Atmospheric Laboratory in northern Ellesmere Island (latitude +80° N). The data reveal that the ground-layer turbulence in the Arctic is often quite weak, even at the comparatively low 610 m altitude of this site. The median and 25th percentile ground-layer seeing, at a height of 20 m, are found to be 0.57 and 0.25 arcsec, respectively. When combined with a free-atmosphere component of 0.30 arcsec, the median and 25th percentile total seeing for this height is 0.68 and 0.42 arcsec, respectively. The median total seeing from a height of 7 m is estimated to be 0.81 arcsec. These values are comparable to those found at the best high-altitude astronomical sites. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. |
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