Mesospheric temperatures derived from three decades of hydroxyl airglow measurements from Longyearbyen, Svalbard (78°N).

The airglow hydroxyl temperature record from Longyearbyen, Svalbard, is updated with data from the last seven seasons (2005/2006-2011/2012). The temperatures are derived from ground-based spectral measurements of the hydroxyl airglow layer, which ranges from 76 to 90 km height. The overall daily average mesospheric temperature for the whole temperature record is 206 K. This is by 3 K less than what Dyrland and Sigernes (2007) reported in their last update on the temperature series. This temperature difference is due to cold winter seasons from 2008 to 2010. 2009/2010 was the coldest winter season ever recorded over Longyearbyen, with a seasonal average of 185 K. Temperature variability within the winter seasons is investigated, and the temperature difference between late December (local minimum) and late January (local maximum) is approximately 8 K. [ABSTRACT FROM AUTHOR]