Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds
<p>Conventional techniques to measure boundary layer clouds such as research aircraft are unable to sample in orographically diverse or densely populated areas. In this paper, we present a newly developed measurement platform on a tethered balloon system (HoloBalloon) to measure in situ vertic...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-02-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/13/925/2020/amt-13-925-2020.pdf |
| _version_ | 1819078951987838976 |
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| author | F. Ramelli A. Beck J. Henneberger U. Lohmann |
| author_facet | F. Ramelli A. Beck J. Henneberger U. Lohmann |
| author_sort | F. Ramelli |
| collection | DOAJ |
| description | <p>Conventional techniques to measure boundary layer clouds such as research aircraft are unable to sample in orographically diverse or densely populated areas. In this paper, we present a newly developed measurement platform on a tethered balloon system (HoloBalloon) to measure in situ vertical profiles of microphysical and meteorological cloud properties up to 1 km above ground. The main component of the HoloBalloon platform is a holographic imager, which uses digital in-line holography to image an ensemble of cloud particles in the size range from small cloud droplets to precipitation-sized particles in a three-dimensional volume. Based on a set of two-dimensional images, information about the phase-resolved particle size distribution, shape and spatial distribution can be obtained. The velocity-independent sample volume makes holographic imagers particularly well suited for measurements on a balloon. The unique combination of holography and balloon-borne measurements allows for observations with high spatial resolution, covering cloud structures from the kilometer down to the millimeter scale.</p>
<p>The potential of the measurement technique in studying boundary layer clouds is demonstrated on the basis of a case study. We present observations of a supercooled low stratus cloud during a Bise situation over the Swiss Plateau in February 2018. In situ microphysical profiles up to 700 m altitude above the ground were performed at temperatures down to <span class="inline-formula">−8</span> <span class="inline-formula"><sup>∘</sup></span>C and wind speeds up to 15 m s<span class="inline-formula"><sup>−1</sup></span>. We were able to capture unique microphysical signatures in stratus clouds, in the form of inhomogeneities in the cloud droplet number concentration and in cloud droplet size, from the kilometer down to the meter scale.</p> |
| first_indexed | 2024-12-21T19:21:16Z |
| format | Article |
| id | doaj.art-e59871b5c2dd40e6a1d3a7698a1a6af2 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-21T19:21:16Z |
| publishDate | 2020-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-e59871b5c2dd40e6a1d3a7698a1a6af22022-12-21T18:52:56ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482020-02-011392593910.5194/amt-13-925-2020Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer cloudsF. RamelliA. BeckJ. HennebergerU. Lohmann<p>Conventional techniques to measure boundary layer clouds such as research aircraft are unable to sample in orographically diverse or densely populated areas. In this paper, we present a newly developed measurement platform on a tethered balloon system (HoloBalloon) to measure in situ vertical profiles of microphysical and meteorological cloud properties up to 1 km above ground. The main component of the HoloBalloon platform is a holographic imager, which uses digital in-line holography to image an ensemble of cloud particles in the size range from small cloud droplets to precipitation-sized particles in a three-dimensional volume. Based on a set of two-dimensional images, information about the phase-resolved particle size distribution, shape and spatial distribution can be obtained. The velocity-independent sample volume makes holographic imagers particularly well suited for measurements on a balloon. The unique combination of holography and balloon-borne measurements allows for observations with high spatial resolution, covering cloud structures from the kilometer down to the millimeter scale.</p> <p>The potential of the measurement technique in studying boundary layer clouds is demonstrated on the basis of a case study. We present observations of a supercooled low stratus cloud during a Bise situation over the Swiss Plateau in February 2018. In situ microphysical profiles up to 700 m altitude above the ground were performed at temperatures down to <span class="inline-formula">−8</span> <span class="inline-formula"><sup>∘</sup></span>C and wind speeds up to 15 m s<span class="inline-formula"><sup>−1</sup></span>. We were able to capture unique microphysical signatures in stratus clouds, in the form of inhomogeneities in the cloud droplet number concentration and in cloud droplet size, from the kilometer down to the meter scale.</p>https://www.atmos-meas-tech.net/13/925/2020/amt-13-925-2020.pdf |
| spellingShingle | F. Ramelli A. Beck J. Henneberger U. Lohmann Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds Atmospheric Measurement Techniques |
| title | Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds |
| title_full | Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds |
| title_fullStr | Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds |
| title_full_unstemmed | Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds |
| title_short | Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds |
| title_sort | using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds |
| url | https://www.atmos-meas-tech.net/13/925/2020/amt-13-925-2020.pdf |
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