Shape dependence of snow crystal fall speed
Improved snowfall predictions require accurate knowledge of the properties of ice crystals and snow particles, such as their size, cross-sectional area, shape, and fall speed. The fall speed of ice particles is a critical parameter for the representation of ice clouds and snow in atmospheric numeric...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00056592 2023-05-15T17:04:21+02:00 Shape dependence of snow crystal fall speed Vázquez-Martín, Sandra Kuhn, Thomas Eliasson, Salomon 2021-05 electronic https://doi.org/10.5194/acp-21-7545-2021 https://noa.gwlb.de/receive/cop_mods_00056592 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00056243/acp-21-7545-2021.pdf https://acp.copernicus.org/articles/21/7545/2021/acp-21-7545-2021.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-21-7545-2021 https://noa.gwlb.de/receive/cop_mods_00056592 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00056243/acp-21-7545-2021.pdf https://acp.copernicus.org/articles/21/7545/2021/acp-21-7545-2021.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2021 ftnonlinearchiv https://doi.org/10.5194/acp-21-7545-2021 2022-02-08T22:34:00Z Improved snowfall predictions require accurate knowledge of the properties of ice crystals and snow particles, such as their size, cross-sectional area, shape, and fall speed. The fall speed of ice particles is a critical parameter for the representation of ice clouds and snow in atmospheric numerical models, as it determines the rate of removal of ice from the modelled clouds. Fall speed is also required for snowfall predictions alongside other properties such as ice particle size, cross-sectional area, and shape. For example, shape is important as it strongly influences the scattering properties of these ice particles and thus their response to remote sensing techniques. This work analyzes fall speed as a function of particle size (maximum dimension), cross-sectional area, and shape using ground-based in situ measurements. The measurements for this study were done in Kiruna, Sweden, during the snowfall seasons of 2014 to 2019, using the ground-based in situ instrument Dual Ice Crystal Imager (D-ICI). The resulting data consist of high-resolution images of falling hydrometeors from two viewing geometries that are used to determine particle size (maximum dimension), cross-sectional area, area ratio, orientation, and the fall speed of individual particles. The selected dataset covers sizes from about 0.06 to 3.2 mm and fall speeds from 0.06 to 1.6 m s−1. Relationships between particle size, cross-sectional area, and fall speed are studied for different shapes. The data show in general low correlations to fitted fall speed relationships due to large spread observed in fall speed. After binning the data according to size or cross-sectional area, correlations improve, and we can report reliable parameterizations of fall speed vs. particle size or cross-sectional area for part of the shapes. For most of these shapes, the fall speed is better correlated with cross-sectional area than with particle size. The effects of orientation and area ratio on the fall speed are also studied, and measurements show that vertically oriented particles fall faster on average. However, most particles for which orientation can be defined fall horizontally. Article in Journal/Newspaper Kiruna Niedersächsisches Online-Archiv NOA Kiruna Atmospheric Chemistry and Physics 21 10 7545 7565 |
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article Verlagsveröffentlichung Vázquez-Martín, Sandra Kuhn, Thomas Eliasson, Salomon Shape dependence of snow crystal fall speed |
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article Verlagsveröffentlichung |
description |
Improved snowfall predictions require accurate knowledge of the properties of ice crystals and snow particles, such as their size, cross-sectional area, shape, and fall speed. The fall speed of ice particles is a critical parameter for the representation of ice clouds and snow in atmospheric numerical models, as it determines the rate of removal of ice from the modelled clouds. Fall speed is also required for snowfall predictions alongside other properties such as ice particle size, cross-sectional area, and shape. For example, shape is important as it strongly influences the scattering properties of these ice particles and thus their response to remote sensing techniques. This work analyzes fall speed as a function of particle size (maximum dimension), cross-sectional area, and shape using ground-based in situ measurements. The measurements for this study were done in Kiruna, Sweden, during the snowfall seasons of 2014 to 2019, using the ground-based in situ instrument Dual Ice Crystal Imager (D-ICI). The resulting data consist of high-resolution images of falling hydrometeors from two viewing geometries that are used to determine particle size (maximum dimension), cross-sectional area, area ratio, orientation, and the fall speed of individual particles. The selected dataset covers sizes from about 0.06 to 3.2 mm and fall speeds from 0.06 to 1.6 m s−1. Relationships between particle size, cross-sectional area, and fall speed are studied for different shapes. The data show in general low correlations to fitted fall speed relationships due to large spread observed in fall speed. After binning the data according to size or cross-sectional area, correlations improve, and we can report reliable parameterizations of fall speed vs. particle size or cross-sectional area for part of the shapes. For most of these shapes, the fall speed is better correlated with cross-sectional area than with particle size. The effects of orientation and area ratio on the fall speed are also studied, and measurements show that vertically oriented particles fall faster on average. However, most particles for which orientation can be defined fall horizontally. |
format |
Article in Journal/Newspaper |
author |
Vázquez-Martín, Sandra Kuhn, Thomas Eliasson, Salomon |
author_facet |
Vázquez-Martín, Sandra Kuhn, Thomas Eliasson, Salomon |
author_sort |
Vázquez-Martín, Sandra |
title |
Shape dependence of snow crystal fall speed |
title_short |
Shape dependence of snow crystal fall speed |
title_full |
Shape dependence of snow crystal fall speed |
title_fullStr |
Shape dependence of snow crystal fall speed |
title_full_unstemmed |
Shape dependence of snow crystal fall speed |
title_sort |
shape dependence of snow crystal fall speed |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/acp-21-7545-2021 https://noa.gwlb.de/receive/cop_mods_00056592 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00056243/acp-21-7545-2021.pdf https://acp.copernicus.org/articles/21/7545/2021/acp-21-7545-2021.pdf |
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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-21-7545-2021 https://noa.gwlb.de/receive/cop_mods_00056592 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00056243/acp-21-7545-2021.pdf https://acp.copernicus.org/articles/21/7545/2021/acp-21-7545-2021.pdf |
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https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
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CC-BY |
op_doi |
https://doi.org/10.5194/acp-21-7545-2021 |
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Atmospheric Chemistry and Physics |
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21 |
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10 |
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7545 |
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7565 |
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