Noctilucent clouds and the mesospheric water vapour: the past decade
The topic of this paper is the sensitivity of the brightness of noctilucent clouds (NLC) on the ambient water vapour mixing ratio f(H 2 O). Firstly, we use state-of-the-art models of NLC layer formation to predict NLC brightness changes in response to changes in the 80km mixing ratio f(H 2 O) for th...
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ftdoajarticles:oai:doaj.org/article:5f8e86a7477f451aa7f385aec9dbea46 2023-05-15T13:11:23+02:00 Noctilucent clouds and the mesospheric water vapour: the past decade U. von Zahn G. Baumgarten U. Berger J. Fiedler P. Hartogh 2004-01-01T00:00:00Z https://doaj.org/article/5f8e86a7477f451aa7f385aec9dbea46 EN eng Copernicus Publications http://www.atmos-chem-phys.net/4/2449/2004/acp-4-2449-2004.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 https://doaj.org/article/5f8e86a7477f451aa7f385aec9dbea46 Atmospheric Chemistry and Physics, Vol 4, Iss 11/12, Pp 2449-2464 (2004) Physics QC1-999 Chemistry QD1-999 article 2004 ftdoajarticles 2022-12-30T23:36:22Z The topic of this paper is the sensitivity of the brightness of noctilucent clouds (NLC) on the ambient water vapour mixing ratio f(H 2 O). Firstly, we use state-of-the-art models of NLC layer formation to predict NLC brightness changes in response to changes in the 80km mixing ratio f(H 2 O) for the two cases of ground-based 532nm lidar observations at 69° N and for hemispheric satellite SBUV observations at 252nm wavelength. In this study, we include a re-evaluation of the sensitivity of NLC brightness to changes in solar Lyman α flux. Secondly, we review observations of episodic changes in f(H 2 O) and those in NLC brightness, the former being available since 1992, the latter since 1979. To this review, we add a new series of observations of f(H 2 O), performed in the Arctic summer at the ALOMAR observatory. The episodic change exhibited by the Arctic summer means of f(H 2 O) turns out to be quite different from all those derived from annual means of f(H 2 O). The latter indicate that since 1996 a significant reduction of annually averaged upper mesospheric water vapour has occurred at low, mid, and high latitudes. These decreases of f(H 2 O) have been observed over the same time period in which a slow increase of SBUV NLC albedo has occurred. From this scenario and additional arguments we conclude that the cause for the observed long-term increase in NLC albedo remains to be identified. We close with comments on the very different character of decadal variations in NLC brightness and occurrence rate. Article in Journal/Newspaper albedo Arctic Directory of Open Access Journals: DOAJ Articles Arctic Alomar ENVELOPE(-67.083,-67.083,-68.133,-68.133) |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 U. von Zahn G. Baumgarten U. Berger J. Fiedler P. Hartogh Noctilucent clouds and the mesospheric water vapour: the past decade |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
The topic of this paper is the sensitivity of the brightness of noctilucent clouds (NLC) on the ambient water vapour mixing ratio f(H 2 O). Firstly, we use state-of-the-art models of NLC layer formation to predict NLC brightness changes in response to changes in the 80km mixing ratio f(H 2 O) for the two cases of ground-based 532nm lidar observations at 69° N and for hemispheric satellite SBUV observations at 252nm wavelength. In this study, we include a re-evaluation of the sensitivity of NLC brightness to changes in solar Lyman α flux. Secondly, we review observations of episodic changes in f(H 2 O) and those in NLC brightness, the former being available since 1992, the latter since 1979. To this review, we add a new series of observations of f(H 2 O), performed in the Arctic summer at the ALOMAR observatory. The episodic change exhibited by the Arctic summer means of f(H 2 O) turns out to be quite different from all those derived from annual means of f(H 2 O). The latter indicate that since 1996 a significant reduction of annually averaged upper mesospheric water vapour has occurred at low, mid, and high latitudes. These decreases of f(H 2 O) have been observed over the same time period in which a slow increase of SBUV NLC albedo has occurred. From this scenario and additional arguments we conclude that the cause for the observed long-term increase in NLC albedo remains to be identified. We close with comments on the very different character of decadal variations in NLC brightness and occurrence rate. |
format |
Article in Journal/Newspaper |
author |
U. von Zahn G. Baumgarten U. Berger J. Fiedler P. Hartogh |
author_facet |
U. von Zahn G. Baumgarten U. Berger J. Fiedler P. Hartogh |
author_sort |
U. von Zahn |
title |
Noctilucent clouds and the mesospheric water vapour: the past decade |
title_short |
Noctilucent clouds and the mesospheric water vapour: the past decade |
title_full |
Noctilucent clouds and the mesospheric water vapour: the past decade |
title_fullStr |
Noctilucent clouds and the mesospheric water vapour: the past decade |
title_full_unstemmed |
Noctilucent clouds and the mesospheric water vapour: the past decade |
title_sort |
noctilucent clouds and the mesospheric water vapour: the past decade |
publisher |
Copernicus Publications |
publishDate |
2004 |
url |
https://doaj.org/article/5f8e86a7477f451aa7f385aec9dbea46 |
long_lat |
ENVELOPE(-67.083,-67.083,-68.133,-68.133) |
geographic |
Arctic Alomar |
geographic_facet |
Arctic Alomar |
genre |
albedo Arctic |
genre_facet |
albedo Arctic |
op_source |
Atmospheric Chemistry and Physics, Vol 4, Iss 11/12, Pp 2449-2464 (2004) |
op_relation |
http://www.atmos-chem-phys.net/4/2449/2004/acp-4-2449-2004.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 https://doaj.org/article/5f8e86a7477f451aa7f385aec9dbea46 |
_version_ |
1766247160076042240 |