Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity
Small-scale processes are crucial for the evolution of Stratocumulus and act on scales reaching down to less than one meter. Most large-eddy simulation studies still apply a horizontal resolution of tens of meters, limiting the ability to resolve cloud-driving processes. I investigate such small-sca...
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ftubkoeln:oai:USBKOELN.ub.uni-koeln.de:53928 2023-05-15T14:23:26+02:00 Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity Rauterkus, Robert 2021 application/pdf https://kups.ub.uni-koeln.de/53928/ https://kups.ub.uni-koeln.de/53928/7/large_eddy_simulation_of_arctic_stratocumulus.pdf de eng ger eng https://kups.ub.uni-koeln.de/53928/7/large_eddy_simulation_of_arctic_stratocumulus.pdf Rauterkus, Robert orcid:0000-0001-8288-3203 (2021). Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity. PhD thesis, Universität zu Köln. ddc:500 ddc:530 ddc:550 doc-type:doctoralThesis Text 2021 ftubkoeln 2022-11-09T07:32:08Z Small-scale processes are crucial for the evolution of Stratocumulus and act on scales reaching down to less than one meter. Most large-eddy simulation studies still apply a horizontal resolution of tens of meters, limiting the ability to resolve cloud-driving processes. I investigate such small-scale processes in a reference case that is—based on the recent field campaigns ACLOUD and PASCAL—defined within this thesis to represent a mixed-phase Stratocumulus during Arctic spring. I apply large-eddy simulations with horizontal resolutions of 35m, 10m, 3.5m, and 3m and a vertical resolution of about 3m. My analysis focuses on the resolution sensitivity of cloud-top entrainment processes and the effects of surface heterogeneity structure on the atmospheric boundary layer. First, I find that for a horizontal grid spacing larger than 10m, the effects of small-scale microphysical cooling and turbulent engulfment on cloud-top entrainment are only represented sufficiently for the atmospheric boundary layer bulk profiles but not on a process level. The stratification-limited size of energy-containing eddies violates the assumptions underlying many sub-grid scale models of turbulent mixing. Second, I observe a decrease in cloud-top entrainment for a horizontal resolution coarser than 10m, which results in 15% more cloud water after six hours of simulation and a corresponding optical thickening of the Stratocumulus. Third, I find that structuring surface heterogeneity does not affect zero- and first-order bulk quantities outside the surface layer. A notable sensibility in higher altitudes is only observed for higher-order quantities, which show increased values over structured surface heterogeneity. Fourth, I observe structured surface heterogeneity to form a streamwise elongated, roll-like, secondary circulation perpendicular to the mean wind. Its formation is neither captured by traditional Arctic lead theory nor by the theory of surface heterogeneity effects on cloud-free atmospheric boundary layers. It turns out that ... Doctoral or Postdoctoral Thesis Arctic Arctic Cologne University: KUPS Arctic |
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Cologne University: KUPS |
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ftubkoeln |
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German English |
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ddc:500 ddc:530 ddc:550 |
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ddc:500 ddc:530 ddc:550 Rauterkus, Robert Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity |
topic_facet |
ddc:500 ddc:530 ddc:550 |
description |
Small-scale processes are crucial for the evolution of Stratocumulus and act on scales reaching down to less than one meter. Most large-eddy simulation studies still apply a horizontal resolution of tens of meters, limiting the ability to resolve cloud-driving processes. I investigate such small-scale processes in a reference case that is—based on the recent field campaigns ACLOUD and PASCAL—defined within this thesis to represent a mixed-phase Stratocumulus during Arctic spring. I apply large-eddy simulations with horizontal resolutions of 35m, 10m, 3.5m, and 3m and a vertical resolution of about 3m. My analysis focuses on the resolution sensitivity of cloud-top entrainment processes and the effects of surface heterogeneity structure on the atmospheric boundary layer. First, I find that for a horizontal grid spacing larger than 10m, the effects of small-scale microphysical cooling and turbulent engulfment on cloud-top entrainment are only represented sufficiently for the atmospheric boundary layer bulk profiles but not on a process level. The stratification-limited size of energy-containing eddies violates the assumptions underlying many sub-grid scale models of turbulent mixing. Second, I observe a decrease in cloud-top entrainment for a horizontal resolution coarser than 10m, which results in 15% more cloud water after six hours of simulation and a corresponding optical thickening of the Stratocumulus. Third, I find that structuring surface heterogeneity does not affect zero- and first-order bulk quantities outside the surface layer. A notable sensibility in higher altitudes is only observed for higher-order quantities, which show increased values over structured surface heterogeneity. Fourth, I observe structured surface heterogeneity to form a streamwise elongated, roll-like, secondary circulation perpendicular to the mean wind. Its formation is neither captured by traditional Arctic lead theory nor by the theory of surface heterogeneity effects on cloud-free atmospheric boundary layers. It turns out that ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Rauterkus, Robert |
author_facet |
Rauterkus, Robert |
author_sort |
Rauterkus, Robert |
title |
Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity |
title_short |
Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity |
title_full |
Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity |
title_fullStr |
Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity |
title_full_unstemmed |
Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity |
title_sort |
large-eddy simulation of arctic stratocumulus: process representation and surface heterogeneity |
publishDate |
2021 |
url |
https://kups.ub.uni-koeln.de/53928/ https://kups.ub.uni-koeln.de/53928/7/large_eddy_simulation_of_arctic_stratocumulus.pdf |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Arctic |
genre_facet |
Arctic Arctic |
op_relation |
https://kups.ub.uni-koeln.de/53928/7/large_eddy_simulation_of_arctic_stratocumulus.pdf Rauterkus, Robert orcid:0000-0001-8288-3203 (2021). Large-Eddy Simulation of Arctic Stratocumulus: Process Representation and Surface Heterogeneity. PhD thesis, Universität zu Köln. |
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1766295989315960832 |