A comparison between ground-based observations of noctilucent clouds and Aura satellite data

A comparison is made between ground-based observations of noctilucent clouds (NLCs), obtained with a network of automated digital cameras, and Aura satellite data (the MLS instrument). The Aura data (water vapor and temperature) demonstrate reasonable values around the summer mesopause fostering NLC formation in June through August, when supersaturated air conditions occur. The temperature decrease leads, in general, to amplification of the NLC brightness. The 2- and 5-day planetary waves, extracted from the Aura temperature field, have definite influence on the brightness variations of NLCs. The temperature behavior around the summer mesopause at 60 degrees N demonstrated a remarkable feature, namely, in 2007 the minimum of a Gaussian fitted seasonal temperature variation was observed, on average, 14 days earlier and was broader than the corresponding minimum in 2008. The different temperature climatology resulted in different seasonal variation of NLCs in 2007 and 2008: in particular, the maximum of a Gaussian fitted seasonal variation of the NLC brightness cycle in 2007 was advanced by 12-29 days relative to that in 2008. (C) 2011 Elsevier Ltd. All rights reserved.