A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region
A case study is presented on the formation and evolution of an ice-supersaturated region (ISSR) that was detected by a radiosonde in NE Germany at 06:00UTC 29 November 2000. The ISSR was situated in the vicinity of the outflow region of a warm conveyor belt associated with an intense event of cyclog...
Main Authors: | , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2005
|
Subjects: | |
Online Access: | https://doaj.org/article/0ed8177693c74237b2814140c7bfccce |
id |
ftdoajarticles:oai:doaj.org/article:0ed8177693c74237b2814140c7bfccce |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:0ed8177693c74237b2814140c7bfccce 2023-05-15T17:36:18+02:00 A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region P. Spichtinger K. Gierens H. Wernli 2005-01-01T00:00:00Z https://doaj.org/article/0ed8177693c74237b2814140c7bfccce EN eng Copernicus Publications http://www.atmos-chem-phys.net/5/973/2005/acp-5-973-2005.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 https://doaj.org/article/0ed8177693c74237b2814140c7bfccce Atmospheric Chemistry and Physics, Vol 5, Iss 4, Pp 973-987 (2005) Physics QC1-999 Chemistry QD1-999 article 2005 ftdoajarticles 2022-12-30T23:44:12Z A case study is presented on the formation and evolution of an ice-supersaturated region (ISSR) that was detected by a radiosonde in NE Germany at 06:00UTC 29 November 2000. The ISSR was situated in the vicinity of the outflow region of a warm conveyor belt associated with an intense event of cyclogenesis in the eastern North Atlantic. Using ECMWF analyses and trajectory calculations it is determined when the air parcels became supersaturated and later subsaturated again. In the case considered, the state of air parcel supersaturation can last for longer than 24h. The ISSR was unusually thick: while the mean vertical extension of ISSRs in NE Germany is about 500m, the one investigated here reached 3km. The ice-supersaturated region investigated was bordered both vertically and horizontally by strongly subsaturated air. Near the path of the radiosonde the ISSR was probably cloud free, as inferred from METEOSAT infrared images. However, at other locations within the ISSR it is probable that there were cirrus clouds. Relative humidity measurements obtained by the Lindenberg radiosonde are used to correct the negative bias of the ECMWF humidity and to construct two-dimensional maps of ice supersaturation over Europe during the considered period. A systematic backward trajectory analysis for the ISSRs on these maps shows that the ISSR air masses themselves experienced only a moderate upward motion during the previous days, whereas parts of the ISSRs were located just above strongly ascending air masses from the boundary layer. This indicates qualitatively that warm conveyor belts associated with mid-latitude cyclogenesis are disturbances that can induce the formation of ISSRs in the upper troposphere. The ISSR maps also lead us to a new perception of ISSRs as large dynamic regions of supersaturated air where cirrus clouds can be embedded at some locations while there is clear air at others. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Lindenberg ENVELOPE(-59.685,-59.685,-64.924,-64.924) |
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 P. Spichtinger K. Gierens H. Wernli A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
A case study is presented on the formation and evolution of an ice-supersaturated region (ISSR) that was detected by a radiosonde in NE Germany at 06:00UTC 29 November 2000. The ISSR was situated in the vicinity of the outflow region of a warm conveyor belt associated with an intense event of cyclogenesis in the eastern North Atlantic. Using ECMWF analyses and trajectory calculations it is determined when the air parcels became supersaturated and later subsaturated again. In the case considered, the state of air parcel supersaturation can last for longer than 24h. The ISSR was unusually thick: while the mean vertical extension of ISSRs in NE Germany is about 500m, the one investigated here reached 3km. The ice-supersaturated region investigated was bordered both vertically and horizontally by strongly subsaturated air. Near the path of the radiosonde the ISSR was probably cloud free, as inferred from METEOSAT infrared images. However, at other locations within the ISSR it is probable that there were cirrus clouds. Relative humidity measurements obtained by the Lindenberg radiosonde are used to correct the negative bias of the ECMWF humidity and to construct two-dimensional maps of ice supersaturation over Europe during the considered period. A systematic backward trajectory analysis for the ISSRs on these maps shows that the ISSR air masses themselves experienced only a moderate upward motion during the previous days, whereas parts of the ISSRs were located just above strongly ascending air masses from the boundary layer. This indicates qualitatively that warm conveyor belts associated with mid-latitude cyclogenesis are disturbances that can induce the formation of ISSRs in the upper troposphere. The ISSR maps also lead us to a new perception of ISSRs as large dynamic regions of supersaturated air where cirrus clouds can be embedded at some locations while there is clear air at others. |
format |
Article in Journal/Newspaper |
author |
P. Spichtinger K. Gierens H. Wernli |
author_facet |
P. Spichtinger K. Gierens H. Wernli |
author_sort |
P. Spichtinger |
title |
A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
title_short |
A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
title_full |
A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
title_fullStr |
A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
title_full_unstemmed |
A case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
title_sort |
case study on the formation and evolution of ice supersaturation in the vicinity of a warm conveyor belt's outflow region |
publisher |
Copernicus Publications |
publishDate |
2005 |
url |
https://doaj.org/article/0ed8177693c74237b2814140c7bfccce |
long_lat |
ENVELOPE(-59.685,-59.685,-64.924,-64.924) |
geographic |
Lindenberg |
geographic_facet |
Lindenberg |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Atmospheric Chemistry and Physics, Vol 5, Iss 4, Pp 973-987 (2005) |
op_relation |
http://www.atmos-chem-phys.net/5/973/2005/acp-5-973-2005.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 https://doaj.org/article/0ed8177693c74237b2814140c7bfccce |
_version_ |
1766135740747481088 |