Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus
Two-dimensional horizontal fields of cloud optical thickness τ derived from airborne measurements of solar spectral, cloud-reflected radiance are compared with semi-idealized large eddy simulations (LESs) of Arctic stratus performed with the Consortium for Small-scale Modeling (COSMO) atmospheric mo...
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Copernicus Publications
2018
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00041501 2023-05-15T14:52:03+02:00 Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus Schäfer, Michael Loewe, Katharina Ehrlich, André Hoose, Corinna Wendisch, Manfred 2018-09 electronic https://doi.org/10.5194/acp-18-13115-2018 https://noa.gwlb.de/receive/cop_mods_00041501 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00041121/acp-18-13115-2018.pdf https://acp.copernicus.org/articles/18/13115/2018/acp-18-13115-2018.pdf eng eng Copernicus Publications Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-18-13115-2018 https://noa.gwlb.de/receive/cop_mods_00041501 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00041121/acp-18-13115-2018.pdf https://acp.copernicus.org/articles/18/13115/2018/acp-18-13115-2018.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2018 ftnonlinearchiv https://doi.org/10.5194/acp-18-13115-2018 2022-02-08T22:41:36Z Two-dimensional horizontal fields of cloud optical thickness τ derived from airborne measurements of solar spectral, cloud-reflected radiance are compared with semi-idealized large eddy simulations (LESs) of Arctic stratus performed with the Consortium for Small-scale Modeling (COSMO) atmospheric model. The measurements were collected during the Vertical Distribution of Ice in Arctic Clouds (VERDI) campaign carried out in Inuvik, Canada, in April/May 2012. The input for the LESs is obtained from collocated airborne dropsonde observations of a persistent Arctic stratus above the sea-ice-free Beaufort Sea. Simulations are performed for spatial resolutions of 50 m (1.6 km × 1.6 km domain) and 100 m (6.4 km × 6.4 km domain). Macrophysical cloud properties, such as cloud top altitude and vertical extent, are well captured by the COSMO simulations. However, COSMO produces rather homogeneous clouds compared to the measurements, in particular for the simulations with coarser spatial resolution. For both spatial resolutions, the directional structure of the cloud inhomogeneity is well represented by the model. Differences between the individual cases are mainly associated with the wind shear near cloud top and the vertical structure of the atmospheric boundary layer. A sensitivity study changing the wind velocity in COSMO by a vertically constant scaling factor shows that the directional, small-scale cloud inhomogeneity structures can range from 250 to 800 m, depending on the mean wind speed, if the simulated domain is large enough to capture also large-scale structures, which then influence the small-scale structures. For those cases, a threshold wind velocity is identified, which determines when the cloud inhomogeneity stops increasing with increasing wind velocity. Article in Journal/Newspaper Arctic Beaufort Sea Inuvik Sea ice Niedersächsisches Online-Archiv NOA Arctic Canada Inuvik ENVELOPE(-133.610,-133.610,68.341,68.341) Atmospheric Chemistry and Physics 18 17 13115 13133 |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Schäfer, Michael Loewe, Katharina Ehrlich, André Hoose, Corinna Wendisch, Manfred Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus |
topic_facet |
article Verlagsveröffentlichung |
description |
Two-dimensional horizontal fields of cloud optical thickness τ derived from airborne measurements of solar spectral, cloud-reflected radiance are compared with semi-idealized large eddy simulations (LESs) of Arctic stratus performed with the Consortium for Small-scale Modeling (COSMO) atmospheric model. The measurements were collected during the Vertical Distribution of Ice in Arctic Clouds (VERDI) campaign carried out in Inuvik, Canada, in April/May 2012. The input for the LESs is obtained from collocated airborne dropsonde observations of a persistent Arctic stratus above the sea-ice-free Beaufort Sea. Simulations are performed for spatial resolutions of 50 m (1.6 km × 1.6 km domain) and 100 m (6.4 km × 6.4 km domain). Macrophysical cloud properties, such as cloud top altitude and vertical extent, are well captured by the COSMO simulations. However, COSMO produces rather homogeneous clouds compared to the measurements, in particular for the simulations with coarser spatial resolution. For both spatial resolutions, the directional structure of the cloud inhomogeneity is well represented by the model. Differences between the individual cases are mainly associated with the wind shear near cloud top and the vertical structure of the atmospheric boundary layer. A sensitivity study changing the wind velocity in COSMO by a vertically constant scaling factor shows that the directional, small-scale cloud inhomogeneity structures can range from 250 to 800 m, depending on the mean wind speed, if the simulated domain is large enough to capture also large-scale structures, which then influence the small-scale structures. For those cases, a threshold wind velocity is identified, which determines when the cloud inhomogeneity stops increasing with increasing wind velocity. |
format |
Article in Journal/Newspaper |
author |
Schäfer, Michael Loewe, Katharina Ehrlich, André Hoose, Corinna Wendisch, Manfred |
author_facet |
Schäfer, Michael Loewe, Katharina Ehrlich, André Hoose, Corinna Wendisch, Manfred |
author_sort |
Schäfer, Michael |
title |
Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus |
title_short |
Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus |
title_full |
Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus |
title_fullStr |
Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus |
title_full_unstemmed |
Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus |
title_sort |
simulated and observed horizontal inhomogeneities of optical thickness of arctic stratus |
publisher |
Copernicus Publications |
publishDate |
2018 |
url |
https://doi.org/10.5194/acp-18-13115-2018 https://noa.gwlb.de/receive/cop_mods_00041501 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00041121/acp-18-13115-2018.pdf https://acp.copernicus.org/articles/18/13115/2018/acp-18-13115-2018.pdf |
long_lat |
ENVELOPE(-133.610,-133.610,68.341,68.341) |
geographic |
Arctic Canada Inuvik |
geographic_facet |
Arctic Canada Inuvik |
genre |
Arctic Beaufort Sea Inuvik Sea ice |
genre_facet |
Arctic Beaufort Sea Inuvik Sea ice |
op_relation |
Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-18-13115-2018 https://noa.gwlb.de/receive/cop_mods_00041501 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00041121/acp-18-13115-2018.pdf https://acp.copernicus.org/articles/18/13115/2018/acp-18-13115-2018.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/acp-18-13115-2018 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
18 |
container_issue |
17 |
container_start_page |
13115 |
op_container_end_page |
13133 |
_version_ |
1766323171878764544 |