Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 23, 1603-1610, 2005
© Author(s) 2005. This work is distributed under
the Creative Commons Attribution 3.0 License.
27 Jul 2005
The red sky enigma over Svalbard in December 2002: a model using polar stratospheric clouds
N. D. Lloyd1, D. A. Degenstein1, F. Sigernes2, E. J. Llewellyn1, and D. A. Lorentzen2 1ISAS, University of Saskatchewan, Saskatoon, Canada
2The University Centre in Svalbard (UNIS), N-9171 Longyearbyen, Norway
Abstract. An anomalous red glow due to scattered sunlight was observed at Longyearbyen (78° N, 15° E) on 6 December 2002 from 07:30 UT to 13:30 UT when the solar zenith angle varied between 100.7° and 104°. A model for this red sky event using sunlight scattered in a two stage process by Polar Stratospheric Clouds (PSC) at 25km is presented and demonstrated to be feasible. The model requires a significant fraction of the polar vortex, which is cold enough for the formation of ice PSC, to be occupied with PSC with an integrated vertical extinction of approximately 0.037 at 845nm. Given these conditions, the model is able to predict, within an order of magnitude, the spatial distribution of intensities measured by meridional scanning photometers located at Longyearbyen across the visible and near infra-red spectrum.

Keywords. Aerosols and particles; Transmission and scattering of radiation; Polar Meteorology

Citation: Lloyd, N. D., Degenstein, D. A., Sigernes, F., Llewellyn, E. J., and Lorentzen, D. A.: The red sky enigma over Svalbard in December 2002: a model using polar stratospheric clouds, Ann. Geophys., 23, 1603-1610,, 2005.

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