NLC and the background atmosphere above ALOMAR
Noctilucent clouds (NLC) have been measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69° N, 16° E). From 1997 to 2010 NLC were detected during more than 1850 h on 440 different days. Colocated MF-radar measurements and calculations with the Leibniz-Institut...
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ftleibnizopen:oai:oai.leibnizopen.de:C7u3IJEBBwLIz6xGIxy3 2024-09-15T18:25:55+00:00 NLC and the background atmosphere above ALOMAR Fiedler, J. Baumgarten, G. Berger, U. Hoffmann, P. Kaifler, N. Lübken, F.-J. 2011 application/pdf https://doi.org/10.34657/1146 https://oa.tib.eu/renate/handle/123456789/729 eng eng München : European Geopyhsical Union CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ 550 cloud microphysics data set diurnal variation Mie theory polar mesospheric cloud radar imagery Article Text 2011 ftleibnizopen https://doi.org/10.34657/1146 2024-08-05T12:41:46Z Noctilucent clouds (NLC) have been measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69° N, 16° E). From 1997 to 2010 NLC were detected during more than 1850 h on 440 different days. Colocated MF-radar measurements and calculations with the Leibniz-Institute Middle Atmosphere (LIMA-) model are used to characterize the background atmosphere. Temperatures as well as horizontal winds at 83 km altitude show distinct differences during NLC observations compared to when NLC are absent. The seasonally averaged temperature is lower and the winds are stronger westward when NLC are detected. The wind separation is a robust feature as it shows up in measurements as well as in model results and it is consistent with the current understanding that lower temperatures support the existence of ice particles. For the whole 14-year data set there is no statistically significant relation between NLC occurrence and solar Lyman-α radiation. On the other hand NLC occurrence and temperatures at 83 km show a significant anti-correlation, which suggests that the thermal state plays a major role for the existence of ice particles and dominates the pure Lyman-α influence on water vapor during certain years. We find the seasonal mean NLC altitudes to be correlated to both Lyman-α radiation and temperature. NLC above ALOMAR are strongly influenced by atmospheric tides. The cloud water content varies by a factor of 2.8 over the diurnal cycle. Diurnal and semidiurnal amplitudes and phases show some pronounced year-to-year variations. In general, amplitudes as well as phases vary in a different manner. Amplitudes change by a factor of more than 3 and phases vary by up to 7 h. Such variability could impact long-term NLC observations which do not cover the full diurnal cycle. publishedVersion Article in Journal/Newspaper Northern Norway LeibnizOpen (The Leibniz Association) |
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Open Polar |
collection |
LeibnizOpen (The Leibniz Association) |
op_collection_id |
ftleibnizopen |
language |
English |
topic |
550 cloud microphysics data set diurnal variation Mie theory polar mesospheric cloud radar imagery |
spellingShingle |
550 cloud microphysics data set diurnal variation Mie theory polar mesospheric cloud radar imagery Fiedler, J. Baumgarten, G. Berger, U. Hoffmann, P. Kaifler, N. Lübken, F.-J. NLC and the background atmosphere above ALOMAR |
topic_facet |
550 cloud microphysics data set diurnal variation Mie theory polar mesospheric cloud radar imagery |
description |
Noctilucent clouds (NLC) have been measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69° N, 16° E). From 1997 to 2010 NLC were detected during more than 1850 h on 440 different days. Colocated MF-radar measurements and calculations with the Leibniz-Institute Middle Atmosphere (LIMA-) model are used to characterize the background atmosphere. Temperatures as well as horizontal winds at 83 km altitude show distinct differences during NLC observations compared to when NLC are absent. The seasonally averaged temperature is lower and the winds are stronger westward when NLC are detected. The wind separation is a robust feature as it shows up in measurements as well as in model results and it is consistent with the current understanding that lower temperatures support the existence of ice particles. For the whole 14-year data set there is no statistically significant relation between NLC occurrence and solar Lyman-α radiation. On the other hand NLC occurrence and temperatures at 83 km show a significant anti-correlation, which suggests that the thermal state plays a major role for the existence of ice particles and dominates the pure Lyman-α influence on water vapor during certain years. We find the seasonal mean NLC altitudes to be correlated to both Lyman-α radiation and temperature. NLC above ALOMAR are strongly influenced by atmospheric tides. The cloud water content varies by a factor of 2.8 over the diurnal cycle. Diurnal and semidiurnal amplitudes and phases show some pronounced year-to-year variations. In general, amplitudes as well as phases vary in a different manner. Amplitudes change by a factor of more than 3 and phases vary by up to 7 h. Such variability could impact long-term NLC observations which do not cover the full diurnal cycle. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Fiedler, J. Baumgarten, G. Berger, U. Hoffmann, P. Kaifler, N. Lübken, F.-J. |
author_facet |
Fiedler, J. Baumgarten, G. Berger, U. Hoffmann, P. Kaifler, N. Lübken, F.-J. |
author_sort |
Fiedler, J. |
title |
NLC and the background atmosphere above ALOMAR |
title_short |
NLC and the background atmosphere above ALOMAR |
title_full |
NLC and the background atmosphere above ALOMAR |
title_fullStr |
NLC and the background atmosphere above ALOMAR |
title_full_unstemmed |
NLC and the background atmosphere above ALOMAR |
title_sort |
nlc and the background atmosphere above alomar |
publisher |
München : European Geopyhsical Union |
publishDate |
2011 |
url |
https://doi.org/10.34657/1146 https://oa.tib.eu/renate/handle/123456789/729 |
genre |
Northern Norway |
genre_facet |
Northern Norway |
op_rights |
CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ |
op_doi |
https://doi.org/10.34657/1146 |
_version_ |
1810466380840960000 |