Gravity wave influence on NLC: experimental results from ALOMAR, 69° N
The influence of gravity waves on noctilucent clouds (NLC) at ALOMAR (69° N) is analysed 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 r...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2013-12-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/13/11951/2013/acp-13-11951-2013.pdf |
| Summary: | The influence of gravity waves on noctilucent clouds (NLC) at ALOMAR
(69° N) is analysed 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 dataset
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 dataset 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. |
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| ISSN: | 1680-7316 1680-7324 |