In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus
Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time, these clouds absorb the infrared radiation from the Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size...
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Luleå tekniska universitet, Rymdteknik
2016
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ftluleatu:oai:DiVA.org:ltu-7503 2024-04-28T08:27:30+00:00 In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus Kuhn, Thomas Heymsfield, Andrew J. 2016 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-7503 https://doi.org/10.1007/s00024-016-1324-x eng eng LuleÃ¥ tekniska universitet, Rymdteknik National Center for Atmospheric Research, Boulder, CO, USA Pure and Applied Geophysics, 0033-4553, 2016, 173:9, s. 3065-3084 orcid:0000-0003-3701-7925 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-7503 doi:10.1007/s00024-016-1324-x ISI:000382941400006 Scopus 2-s2.0-84986550413 Local 5e5db84f-dc26-4e5f-8754-75ceef750aff info:eu-repo/semantics/openAccess small ice particles cirrus in situ measurements volume extinction balloon-borne Aerospace Engineering Rymd- och flygteknik Article in journal info:eu-repo/semantics/article text 2016 ftluleatu https://doi.org/10.1007/s00024-016-1324-x 2024-04-09T23:35:59Z Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time, these clouds absorb the infrared radiation from the Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size distributions and particle shapes. Knowledge of these cloud properties is also needed for calibrating and validating passive and active remote sensors. Ice particles of sizes below 100 µm are inherently difficult to measure with aircraft-mounted probes due to issues with resolution, sizing, and size-dependent sampling volume. Furthermore, artefacts are produced by shattering of particles on the leading surfaces of the aircraft probes when particles several hundred microns or larger are present. Here, we report on a series of balloon-borne in situ measurements that were carried out at a high-latitude location, Kiruna in northern Sweden (68N 21E). The method used here avoids these issues experienced with the aircraft probes. Furthermore, with a balloon-borne instrument, data are collected as vertical profiles, more useful for calibrating or evaluating remote sensing measurements than data collected along horizontal traverses. Particles are collected on an oil-coated film at a sampling speed given directly by the ascending rate of the balloon, 4 m s−1. The collecting film is advanced uniformly inside the instrument so that an always unused section of the film is exposed to ice particles, which are measured by imaging shortly after sampling. The high optical resolution of about 4 µm together with a pixel resolution of 1.65 µm allows particle detection at sizes of 10 µm and larger. For particles that are 20 µm (12 pixel) in size or larger, the shape can be recognized. The sampling volume, 130 cm3 s−1, is well defined and independent of particle size. With the encountered number concentrations of between 4 and 400 L−1, this required about 90- to 4-s sampling times to determine particle size distributions of cloud ... Article in Journal/Newspaper Kiruna Northern Sweden Luleå University of Technology Publications (DiVA) Pure and Applied Geophysics 173 9 3065 3084 |
institution |
Open Polar |
collection |
Luleå University of Technology Publications (DiVA) |
op_collection_id |
ftluleatu |
language |
English |
topic |
small ice particles cirrus in situ measurements volume extinction balloon-borne Aerospace Engineering Rymd- och flygteknik |
spellingShingle |
small ice particles cirrus in situ measurements volume extinction balloon-borne Aerospace Engineering Rymd- och flygteknik Kuhn, Thomas Heymsfield, Andrew J. In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus |
topic_facet |
small ice particles cirrus in situ measurements volume extinction balloon-borne Aerospace Engineering Rymd- och flygteknik |
description |
Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time, these clouds absorb the infrared radiation from the Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size distributions and particle shapes. Knowledge of these cloud properties is also needed for calibrating and validating passive and active remote sensors. Ice particles of sizes below 100 µm are inherently difficult to measure with aircraft-mounted probes due to issues with resolution, sizing, and size-dependent sampling volume. Furthermore, artefacts are produced by shattering of particles on the leading surfaces of the aircraft probes when particles several hundred microns or larger are present. Here, we report on a series of balloon-borne in situ measurements that were carried out at a high-latitude location, Kiruna in northern Sweden (68N 21E). The method used here avoids these issues experienced with the aircraft probes. Furthermore, with a balloon-borne instrument, data are collected as vertical profiles, more useful for calibrating or evaluating remote sensing measurements than data collected along horizontal traverses. Particles are collected on an oil-coated film at a sampling speed given directly by the ascending rate of the balloon, 4 m s−1. The collecting film is advanced uniformly inside the instrument so that an always unused section of the film is exposed to ice particles, which are measured by imaging shortly after sampling. The high optical resolution of about 4 µm together with a pixel resolution of 1.65 µm allows particle detection at sizes of 10 µm and larger. For particles that are 20 µm (12 pixel) in size or larger, the shape can be recognized. The sampling volume, 130 cm3 s−1, is well defined and independent of particle size. With the encountered number concentrations of between 4 and 400 L−1, this required about 90- to 4-s sampling times to determine particle size distributions of cloud ... |
format |
Article in Journal/Newspaper |
author |
Kuhn, Thomas Heymsfield, Andrew J. |
author_facet |
Kuhn, Thomas Heymsfield, Andrew J. |
author_sort |
Kuhn, Thomas |
title |
In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus |
title_short |
In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus |
title_full |
In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus |
title_fullStr |
In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus |
title_full_unstemmed |
In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus |
title_sort |
in situ balloon-borne ice particle imaging in high-latitude cirrus |
publisher |
Luleå tekniska universitet, Rymdteknik |
publishDate |
2016 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-7503 https://doi.org/10.1007/s00024-016-1324-x |
genre |
Kiruna Northern Sweden |
genre_facet |
Kiruna Northern Sweden |
op_relation |
Pure and Applied Geophysics, 0033-4553, 2016, 173:9, s. 3065-3084 orcid:0000-0003-3701-7925 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-7503 doi:10.1007/s00024-016-1324-x ISI:000382941400006 Scopus 2-s2.0-84986550413 Local 5e5db84f-dc26-4e5f-8754-75ceef750aff |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1007/s00024-016-1324-x |
container_title |
Pure and Applied Geophysics |
container_volume |
173 |
container_issue |
9 |
container_start_page |
3065 |
op_container_end_page |
3084 |
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