Composition and Chemistry
First evidence of a 27 day solar signature in noctilucent cloud occurrence frequency
Article first published online: 30 MAR 2010
Copyright 2010 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 115, Issue D1, 16 January 2010
How to Cite
2010), First evidence of a 27 day solar signature in noctilucent cloud occurrence frequency, J. Geophys. Res., 115, D00I12, doi:10.1029/2009JD012359., , , , , , and (
- Issue published online: 30 MAR 2010
- Article first published online: 30 MAR 2010
- Manuscript Accepted: 28 SEP 2009
- Manuscript Revised: 24 SEP 2009
- Manuscript Received: 30 APR 2009
- noctilucent clouds;
- 27 day solar variability
 This paper presents evidence of a connection between the 27 day modulation of the solar activity and noctilucent cloud (NLC) occurrence frequency as measured by the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and solar backscatter ultraviolet (SBUV) instruments. Observations show anticorrelations significant at the 90% confidence level between noctilucent cloud occurrence rate anomalies and Lyman-α irradiance variation during several seasons in both hemispheres. A superposed epoch analysis confirms these results and also reveals a clear recurrence pattern in noctilucent clouds occurrence anomalies with a ∼27 day period. The superposed epoch analysis also shows that the maximum NLC response in the Northern Hemisphere is clearly localized at 0 day phase lag, while in the Southern Hemisphere the maximum response is broader and occurs at 0 ± 2 day phase lag. Microwave Limb Sounder mesospheric products suggest that the more likely driver for the variation in NLC occurrence is temperature instead of water vapor, but the mechanisms responsible for the observed variations are not yet fully understood.