Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 14, 12133-12142, 2014
http://www.atmos-chem-phys.net/14/12133/2014/
doi:10.5194/acp-14-12133-2014
© Author(s) 2014. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
18 Nov 2014
Characteristics and sources of gravity waves observed in noctilucent cloud over Norway
T. D. Demissie1,2, P. J. Espy1,2, N. H. Kleinknecht1, M. Hatlen1, N. Kaifler3, and G. Baumgarten3 1Norwegian University of Science and Technology (NTNU), Department of Physics, Trondheim, Norway
2Birkeland Centre for Space Science, Bergen, Norway
3Leibniz-Institut für Atmosphärenphysik e. V., 18225 Kühlungsborn, Germany
Abstract. Four years of noctilucent cloud (NLC) images from an automated digital camera in Trondheim and results from a ray-tracing model are used to extend the climatology of gravity waves to higher latitudes and to identify their sources during summertime. The climatology of the summertime gravity waves detected in NLC between 64 and 74° N is similar to that observed between 60 and 64° N by Pautet et al. (2011). The direction of propagation of gravity waves observed in the NLC north of 64° N is a continuation of the north and northeast propagation as observed in south of 64° N. However, a unique population of fast, short wavelength waves propagating towards the SW is observed in the NLC, which is consistent with transverse instabilities generated in situ by breaking gravity waves (Fritts and Alexander, 2003). The relative amplitude of the waves observed in the NLC Mie scatter have been combined with ray-tracing results to show that waves propagating from near the tropopause, rather than those resulting from secondary generation in the stratosphere or mesosphere, are more likely to be the sources of the prominent wave structures observed in the NLC. The coastal region of Norway along the latitude of 70° N is identified as the primary source region of the waves generated near the tropopause.

Citation: Demissie, T. D., Espy, P. J., Kleinknecht, N. H., Hatlen, M., Kaifler, N., and Baumgarten, G.: Characteristics and sources of gravity waves observed in noctilucent cloud over Norway, Atmos. Chem. Phys., 14, 12133-12142, doi:10.5194/acp-14-12133-2014, 2014.
Publications Copernicus
Download
Short summary
Summertime gravity waves detected in noctilucent clouds (NLCs) between 64◦ and 74◦N are found to have a similar climatology to those observed between 60◦ and 64◦N, and their direction of propagation is to the north and northeast as observed south of 64◦N. However, a unique population of fast, short wavelength waves propagating towards the SW is observed in the NLC. The sources of the prominent wave structures observed in the NLC are likely to be from waves propagating from near the tropopause.
Summertime gravity waves detected in noctilucent clouds (NLCs) between 64◦ and 74◦N are...
Share