Atmos. Chem. Phys. Discuss., 13, 20049-20079, 2013
© Author(s) 2013. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Gravity wave influence on NLC: experimental results from ALOMAR, 69° N
H. Wilms1, M. Rapp1,2, P. Hoffmann3, J. Fiedler3, and G. Baumgarten3
1Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
2Meteorologisches Institut München, Ludwig-Maximilians-Universität München, Munich, Germany
3Leibniz Institute of Atmospheric Physics, Schlossstr. 6, 18225 Kühlungsborn, Germany

Abstract. The influence of gravity waves on noctilucent clouds (NLC) at ALOMAR (69° N) is analyzed by relating gravity wave activity to NLC occurrence from common-volume measurements. Gravity wave kinetic energies are derived from MF-radar wind data and filtered into different period ranges by wavelet transformation. From the data set covering the years 1999–2011 a direct correlation between gravity wave kinetic energy and NLC occurrence is not found. I.e., NLC appear independently of the simultaneously measured gravity wave kinetic energy. In addition, gravity wave activity is divided into weak and strong activity as compared to a 13 yr mean. The NLC occurrence rates during strong and weak activity are calculated separately for a given wave period and compared to each other. Again, for the full data set no dependence of NLC occurrence on relative gravity wave activity is found. However, concentrating on 12 h of NLC detections during 2008, we do find an NLC-amplification with strong long-period gravity wave occurrence. Our analysis hence confirms previous findings that in general NLC at ALOMAR are not predominantly driven by gravity waves while exceptions to this rule are at least possible.

Citation: Wilms, H., Rapp, M., Hoffmann, P., Fiedler, J., and Baumgarten, G.: Gravity wave influence on NLC: experimental results from ALOMAR, 69° N, Atmos. Chem. Phys. Discuss., 13, 20049-20079, doi:10.5194/acpd-13-20049-2013, 2013.
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