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Ann. Geophys., 24, 1245-1255, 2006
www.ann-geophys.net/24/1245/2006/
© European Geosciences Union 2006
Polar mesosphere winter echoes during MaCWAVE
S. Kirkwood1, E. Belova1, U. Blum2,*, C. Croskey3, P. Dalin1, K.-H. Fricke2, R. A. Goldberg4, J. Manninen5, J. D. Mitchell3, and F. Schmidlin6
1Swedish Institute of Space Physics, Box 812, 98128 Kiruna, Sweden
2Physikalisches Institut der Universität Bonn, 53115 Bonn, Germany
3EE Dept., Pennsylvania State University, University Park, PA 16802, USA
4NASA/GSFC, Code 612.3, Greenbelt, MD20771, USA
5Sodankylä Geophysical Observatory, T¨ahteläntie 62 FIN-99600 Sodankylä, Finland
6Code 972, NASA/GSFC/Wallops Flight Facility, Wallops Is. VA 23337, USA
*now at: Forsvarets Forskningsinstitutt, N-2027 Kjeller, Norway
Abstract. During the MaCWAVE winter campaign in January 2003, layers of enhanced echo
power known as PMWE (Polar Mesosphere Winter Echoes) were detected by the
ESRAD 52 MHz radar on several occasions. The cause of these echoes is
unclear and here we use observations by meteorological and sounding rockets
and by lidar to test whether neutral turbulence or aerosol layers might be
responsible. PMWE were detected within 30 min of meteorological rocket
soundings (falling spheres) on 5 separate days. The observations from the
meteorological rockets show that, in most cases, conditions likely to be
associated with neutral atmospheric turbulence are not observed at the
heights of the PMWE. Observations by instrumented sounding rockets confirm
low levels of turbulence and indicate considerable small-scale structure in
charge density profiles. Comparison of falling sphere and lidar data, on the
other hand, show that any contribution of aerosol scatter to the lidar
signal at PMWE heights is less than the detection threshold of about 10%.
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