Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR
From 1997 to 2003, noctilucent clouds (NLC) were observed by lidar above the ALOMAR observatory in Northern Norway (69° N) during a total of 1880measurement hours. This data set contains NLC signatures for 640h, covering all local times, even during the highest solar background conditions. After dat...
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ftdoajarticles:oai:doaj.org/article:0b5ddc9f7d9846ad8489a183e2af7853 2023-05-15T17:43:33+02:00 Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR J. Fiedler G. Baumgarten G. von Cossart 2005-06-01T00:00:00Z https://doi.org/10.5194/angeo-23-1175-2005 https://doaj.org/article/0b5ddc9f7d9846ad8489a183e2af7853 EN eng Copernicus Publications https://www.ann-geophys.net/23/1175/2005/angeo-23-1175-2005.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-23-1175-2005 0992-7689 1432-0576 https://doaj.org/article/0b5ddc9f7d9846ad8489a183e2af7853 Annales Geophysicae, Vol 23, Pp 1175-1181 (2005) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2005 ftdoajarticles https://doi.org/10.5194/angeo-23-1175-2005 2022-12-31T12:29:43Z From 1997 to 2003, noctilucent clouds (NLC) were observed by lidar above the ALOMAR observatory in Northern Norway (69° N) during a total of 1880measurement hours. This data set contains NLC signatures for 640h, covering all local times, even during the highest solar background conditions. After data limitation imposing a threshold value of 4x10 -10 m -1 sr -1 for the volume backscatter coefficient of the NLC particles, a measure for the cloud brightness, local time dependencies of the NLC occurrence frequency, altitude, and brightness were determined. On average, over the 7years NLC occurred during the whole day and preferably in the early morning hours, with a maximum occurrence frequency of ~40% between 4 and 7LT. Splitting the data into weak and strong clouds yields almost identical amplitudes of diurnal and semidiurnal variations for the occurrence of weak clouds, whereas the strong clouds are dominated by the diurnal variation. NLC occurrence, altitude, as well as brightness, show a remarkable persistence concerning diurnal and semidiurnal variations from 1997 to 2003, suggesting that NLC above ALOMAR are significantly controlled by atmospheric tides. The observed mean anti-phase behavior between cloud altitude and brightness is attributed to a phase shift between the semidiurnal components by ~6h. Investigation of data for each individual year regarding the prevailing oscillation periods of the NLC parameters showed different phase relationships, leading to a complex variability in the cloud parameters. Article in Journal/Newspaper Northern Norway Directory of Open Access Journals: DOAJ Articles Alomar ENVELOPE(-67.083,-67.083,-68.133,-68.133) Norway Annales Geophysicae 23 4 1175 1181 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 J. Fiedler G. Baumgarten G. von Cossart Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
From 1997 to 2003, noctilucent clouds (NLC) were observed by lidar above the ALOMAR observatory in Northern Norway (69° N) during a total of 1880measurement hours. This data set contains NLC signatures for 640h, covering all local times, even during the highest solar background conditions. After data limitation imposing a threshold value of 4x10 -10 m -1 sr -1 for the volume backscatter coefficient of the NLC particles, a measure for the cloud brightness, local time dependencies of the NLC occurrence frequency, altitude, and brightness were determined. On average, over the 7years NLC occurred during the whole day and preferably in the early morning hours, with a maximum occurrence frequency of ~40% between 4 and 7LT. Splitting the data into weak and strong clouds yields almost identical amplitudes of diurnal and semidiurnal variations for the occurrence of weak clouds, whereas the strong clouds are dominated by the diurnal variation. NLC occurrence, altitude, as well as brightness, show a remarkable persistence concerning diurnal and semidiurnal variations from 1997 to 2003, suggesting that NLC above ALOMAR are significantly controlled by atmospheric tides. The observed mean anti-phase behavior between cloud altitude and brightness is attributed to a phase shift between the semidiurnal components by ~6h. Investigation of data for each individual year regarding the prevailing oscillation periods of the NLC parameters showed different phase relationships, leading to a complex variability in the cloud parameters. |
format |
Article in Journal/Newspaper |
author |
J. Fiedler G. Baumgarten G. von Cossart |
author_facet |
J. Fiedler G. Baumgarten G. von Cossart |
author_sort |
J. Fiedler |
title |
Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR |
title_short |
Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR |
title_full |
Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR |
title_fullStr |
Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR |
title_full_unstemmed |
Mean diurnal variations of noctilucent clouds during 7 years of lidar observations at ALOMAR |
title_sort |
mean diurnal variations of noctilucent clouds during 7 years of lidar observations at alomar |
publisher |
Copernicus Publications |
publishDate |
2005 |
url |
https://doi.org/10.5194/angeo-23-1175-2005 https://doaj.org/article/0b5ddc9f7d9846ad8489a183e2af7853 |
long_lat |
ENVELOPE(-67.083,-67.083,-68.133,-68.133) |
geographic |
Alomar Norway |
geographic_facet |
Alomar Norway |
genre |
Northern Norway |
genre_facet |
Northern Norway |
op_source |
Annales Geophysicae, Vol 23, Pp 1175-1181 (2005) |
op_relation |
https://www.ann-geophys.net/23/1175/2005/angeo-23-1175-2005.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-23-1175-2005 0992-7689 1432-0576 https://doaj.org/article/0b5ddc9f7d9846ad8489a183e2af7853 |
op_doi |
https://doi.org/10.5194/angeo-23-1175-2005 |
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Annales Geophysicae |
container_volume |
23 |
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4 |
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1175 |
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1181 |
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