Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations

Large eddy simulations (LESs) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary layer modification, cloud generation and vertical mixing of aerosols. Due to the presence of a topographically structured island surface in the domain center, the model...

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Published in:Atmospheric Chemistry and Physics
Main Authors: Jähn, M., Muñoz-Esparza, D., Chouza, F., Reitebuch, O., Knoth, O., Haarig, M., Ansmann, A.
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2016
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Online Access:https://doi.org/10.5194/acp-16-651-2016
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spelling ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00043976 2023-05-15T17:36:24+02:00 Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations Jähn, M. Muñoz-Esparza, D. Chouza, F. Reitebuch, O. Knoth, O. Haarig, M. Ansmann, A. 2016-01 electronic https://doi.org/10.5194/acp-16-651-2016 https://noa.gwlb.de/receive/cop_mods_00043976 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043596/acp-16-651-2016.pdf https://acp.copernicus.org/articles/16/651/2016/acp-16-651-2016.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-16-651-2016 https://noa.gwlb.de/receive/cop_mods_00043976 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043596/acp-16-651-2016.pdf https://acp.copernicus.org/articles/16/651/2016/acp-16-651-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/acp-16-651-2016 2022-02-08T22:40:19Z Large eddy simulations (LESs) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary layer modification, cloud generation and vertical mixing of aerosols. Due to the presence of a topographically structured island surface in the domain center, the model setup has to be designed with open lateral boundaries. In order to generate inflow turbulence consistent with the upstream marine boundary layer forcing, we use the cell perturbation method based on finite amplitude potential temperature perturbations. In this work, this method is for the first time tested and validated for moist boundary layer simulations with open lateral boundary conditions. Observational data obtained from the SALTRACE field campaign is used for both model initialization and a comparison with Doppler wind and Raman lidar data. Several numerical sensitivity tests are carried out to demonstrate the problems related to “gray zone modeling” when using coarser spatial grid spacings beyond the inertial subrange of three-dimensional turbulence or when the turbulent marine boundary layer flow is replaced by laminar winds. Especially cloud properties in the downwind area west of Barbados are markedly affected in these kinds of simulations. Results of an additional simulation with a strong trade-wind inversion reveal its effect on cloud layer depth and location. Saharan dust layers that reach Barbados via long-range transport over the North Atlantic are included as passive tracers in the model. Effects of layer thinning, subsidence and turbulent downward transport near the layer bottom at z ≈ 1800 m become apparent. The exact position of these layers and strength of downward mixing is found to be mainly controlled atmospheric stability (especially inversion strength) and wind shear. Comparisons of LES model output with wind lidar data show similarities in the downwind vertical wind structure. Additionally, the model results accurately reproduce the development of the daytime convective boundary layer measured by the Raman lidar. Article in Journal/Newspaper North Atlantic Niedersächsisches Online-Archiv NOA Atmospheric Chemistry and Physics 16 2 651 674
institution Open Polar
collection Niedersächsisches Online-Archiv NOA
op_collection_id ftnonlinearchiv
language English
topic article
Verlagsveröffentlichung
spellingShingle article
Verlagsveröffentlichung
Jähn, M.
Muñoz-Esparza, D.
Chouza, F.
Reitebuch, O.
Knoth, O.
Haarig, M.
Ansmann, A.
Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
topic_facet article
Verlagsveröffentlichung
description Large eddy simulations (LESs) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary layer modification, cloud generation and vertical mixing of aerosols. Due to the presence of a topographically structured island surface in the domain center, the model setup has to be designed with open lateral boundaries. In order to generate inflow turbulence consistent with the upstream marine boundary layer forcing, we use the cell perturbation method based on finite amplitude potential temperature perturbations. In this work, this method is for the first time tested and validated for moist boundary layer simulations with open lateral boundary conditions. Observational data obtained from the SALTRACE field campaign is used for both model initialization and a comparison with Doppler wind and Raman lidar data. Several numerical sensitivity tests are carried out to demonstrate the problems related to “gray zone modeling” when using coarser spatial grid spacings beyond the inertial subrange of three-dimensional turbulence or when the turbulent marine boundary layer flow is replaced by laminar winds. Especially cloud properties in the downwind area west of Barbados are markedly affected in these kinds of simulations. Results of an additional simulation with a strong trade-wind inversion reveal its effect on cloud layer depth and location. Saharan dust layers that reach Barbados via long-range transport over the North Atlantic are included as passive tracers in the model. Effects of layer thinning, subsidence and turbulent downward transport near the layer bottom at z ≈ 1800 m become apparent. The exact position of these layers and strength of downward mixing is found to be mainly controlled atmospheric stability (especially inversion strength) and wind shear. Comparisons of LES model output with wind lidar data show similarities in the downwind vertical wind structure. Additionally, the model results accurately reproduce the development of the daytime convective boundary layer measured by the Raman lidar.
format Article in Journal/Newspaper
author Jähn, M.
Muñoz-Esparza, D.
Chouza, F.
Reitebuch, O.
Knoth, O.
Haarig, M.
Ansmann, A.
author_facet Jähn, M.
Muñoz-Esparza, D.
Chouza, F.
Reitebuch, O.
Knoth, O.
Haarig, M.
Ansmann, A.
author_sort Jähn, M.
title Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
title_short Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
title_full Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
title_fullStr Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
title_full_unstemmed Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
title_sort investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at barbados with large eddy simulations
publisher Copernicus Publications
publishDate 2016
url https://doi.org/10.5194/acp-16-651-2016
https://noa.gwlb.de/receive/cop_mods_00043976
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043596/acp-16-651-2016.pdf
https://acp.copernicus.org/articles/16/651/2016/acp-16-651-2016.pdf
genre North Atlantic
genre_facet North Atlantic
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-16-651-2016
https://noa.gwlb.de/receive/cop_mods_00043976
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043596/acp-16-651-2016.pdf
https://acp.copernicus.org/articles/16/651/2016/acp-16-651-2016.pdf
op_rights uneingeschränkt
info:eu-repo/semantics/openAccess
op_doi https://doi.org/10.5194/acp-16-651-2016
container_title Atmospheric Chemistry and Physics
container_volume 16
container_issue 2
container_start_page 651
op_container_end_page 674
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