Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI)
Accurate predictions of snowfall require good knowledge of the microphysical properties of the snow ice crystals and particles. Shape is an important parameter as it strongly influences the scattering properties of the ice particles, and thus their response to remote sensing techniques such as radar...
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ftdoajarticles:oai:doaj.org/article:2a6bd5e778da4a2e855c04bebd76082e 2023-05-15T17:04:21+02:00 Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) T. Kuhn S. Vázquez-Martín 2020-03-01T00:00:00Z https://doi.org/10.5194/amt-13-1273-2020 https://doaj.org/article/2a6bd5e778da4a2e855c04bebd76082e EN eng Copernicus Publications https://www.atmos-meas-tech.net/13/1273/2020/amt-13-1273-2020.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-13-1273-2020 1867-1381 1867-8548 https://doaj.org/article/2a6bd5e778da4a2e855c04bebd76082e Atmospheric Measurement Techniques, Vol 13, Pp 1273-1285 (2020) Environmental engineering TA170-171 Earthwork. Foundations TA715-787 article 2020 ftdoajarticles https://doi.org/10.5194/amt-13-1273-2020 2022-12-31T00:03:42Z Accurate predictions of snowfall require good knowledge of the microphysical properties of the snow ice crystals and particles. Shape is an important parameter as it strongly influences the scattering properties of the ice particles, and thus their response to remote sensing techniques such as radar measurements. The fall speed of ice particles is another important parameter for both numerical forecast models as well as representation of ice clouds and snow in climate models, as it is responsible for the rate of removal of ice from these models. We describe a new ground-based in situ instrument, the Dual Ice Crystal Imager (D-ICI), to determine snow ice crystal properties and fall speed simultaneously. The instrument takes two high-resolution pictures of the same falling ice particle from two different viewing directions. Both cameras use a microscope-like setup resulting in an image pixel resolution of approximately 4 µ m pixel −1 . One viewing direction is horizontal and is used to determine fall speed by means of a double exposure. For this purpose, two bright flashes of a light-emitting diode behind the camera illuminate the falling ice particle and create this double exposure, and the vertical displacement of the particle provides its fall speed. The other viewing direction is close-to-vertical and is used to provide size and shape information from single-exposure images. This viewing geometry is chosen instead of a horizontal one because shape and size of ice particles as viewed in the vertical direction are more relevant than these properties viewed horizontally, as the vertical fall speed is more strongly influenced by the vertically viewed properties. In addition, a comparison with remote sensing instruments that mostly have a vertical or close-to-vertical viewing geometry is favoured when the particle properties are measured in the same direction. The instrument has been tested in Kiruna, northern Sweden (67.8 ∘ N, 20.4 ∘ E). Measurements are demonstrated with images from different snow events, and the ... Article in Journal/Newspaper Kiruna Northern Sweden Directory of Open Access Journals: DOAJ Articles Kiruna New Ground ENVELOPE(-55.215,-55.215,49.567,49.567) Atmospheric Measurement Techniques 13 3 1273 1285 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
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Environmental engineering TA170-171 Earthwork. Foundations TA715-787 T. Kuhn S. Vázquez-Martín Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) |
topic_facet |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
description |
Accurate predictions of snowfall require good knowledge of the microphysical properties of the snow ice crystals and particles. Shape is an important parameter as it strongly influences the scattering properties of the ice particles, and thus their response to remote sensing techniques such as radar measurements. The fall speed of ice particles is another important parameter for both numerical forecast models as well as representation of ice clouds and snow in climate models, as it is responsible for the rate of removal of ice from these models. We describe a new ground-based in situ instrument, the Dual Ice Crystal Imager (D-ICI), to determine snow ice crystal properties and fall speed simultaneously. The instrument takes two high-resolution pictures of the same falling ice particle from two different viewing directions. Both cameras use a microscope-like setup resulting in an image pixel resolution of approximately 4 µ m pixel −1 . One viewing direction is horizontal and is used to determine fall speed by means of a double exposure. For this purpose, two bright flashes of a light-emitting diode behind the camera illuminate the falling ice particle and create this double exposure, and the vertical displacement of the particle provides its fall speed. The other viewing direction is close-to-vertical and is used to provide size and shape information from single-exposure images. This viewing geometry is chosen instead of a horizontal one because shape and size of ice particles as viewed in the vertical direction are more relevant than these properties viewed horizontally, as the vertical fall speed is more strongly influenced by the vertically viewed properties. In addition, a comparison with remote sensing instruments that mostly have a vertical or close-to-vertical viewing geometry is favoured when the particle properties are measured in the same direction. The instrument has been tested in Kiruna, northern Sweden (67.8 ∘ N, 20.4 ∘ E). Measurements are demonstrated with images from different snow events, and the ... |
format |
Article in Journal/Newspaper |
author |
T. Kuhn S. Vázquez-Martín |
author_facet |
T. Kuhn S. Vázquez-Martín |
author_sort |
T. Kuhn |
title |
Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) |
title_short |
Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) |
title_full |
Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) |
title_fullStr |
Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) |
title_full_unstemmed |
Microphysical properties and fall speed measurements of snow ice crystals using the Dual Ice Crystal Imager (D-ICI) |
title_sort |
microphysical properties and fall speed measurements of snow ice crystals using the dual ice crystal imager (d-ici) |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/amt-13-1273-2020 https://doaj.org/article/2a6bd5e778da4a2e855c04bebd76082e |
long_lat |
ENVELOPE(-55.215,-55.215,49.567,49.567) |
geographic |
Kiruna New Ground |
geographic_facet |
Kiruna New Ground |
genre |
Kiruna Northern Sweden |
genre_facet |
Kiruna Northern Sweden |
op_source |
Atmospheric Measurement Techniques, Vol 13, Pp 1273-1285 (2020) |
op_relation |
https://www.atmos-meas-tech.net/13/1273/2020/amt-13-1273-2020.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-13-1273-2020 1867-1381 1867-8548 https://doaj.org/article/2a6bd5e778da4a2e855c04bebd76082e |
op_doi |
https://doi.org/10.5194/amt-13-1273-2020 |
container_title |
Atmospheric Measurement Techniques |
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13 |
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3 |
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1273 |
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1285 |
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1766058432947814400 |