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Ann. Geophys., 26, 1083-1088, 2008
www.ann-geophys.net/26/1083/2008/
© European Geosciences Union 2008
The thermal structure at the topside and above of polar mesosphere summer echoes over Spitsbergen 78° N
J. Lautenbach, J. Höffner, F.-J. Lübken, and M. Zecha
Leibniz-Institute of Atmospheric Physics, Schlossstraße 6, 18225 Kühlungsborn, Germany
Abstract. Simultaneous measurements of temperature and polar mesosphere summer echoes (PMSE) were performed
at the polar cap (78° N) during summer 2001 and 2003. In summer time the mesopause region
is characterized by extremely low temperatures around 120 K. It is remarkable that PMSE are practically
never observed above 92 km although temperatures are low enough to allow the existence of ice particles.
In this case study we compare the PMSE topside with temperatures measured by the potassium lidar and with
frost point temperatures using water-vapor mixing ratios from models. We find striking discrepancies with
our current understanding of ice particles and temperature in this region. In this case study we
find that the temperature can be more than 20 K lower than the frost point temperature but no PMSE
is observed above 92 km altitude. We show that the lack of PMSE does not necessarily imply that the
temperature is too high.
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