Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data
<p>In situ observations from research aircraft and instrumented ground sites are important contributions to developing our collective understanding of clouds and are used to inform and validate numerical weather and climate models. Unfortunately, biases in these datasets may be present, which...
| Published in: | Atmospheric Measurement Techniques |
|---|---|
| Main Authors: | , , , , , , , |
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-06-01
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| Online Access: | https://www.atmos-meas-tech.net/12/3067/2019/amt-12-3067-2019.pdf |
| _version_ | 1852742385363058688 |
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| author | S. J. O'Shea J. Crosier J. Crosier J. Dorsey J. Dorsey W. Schledewitz I. Crawford S. Borrmann S. Borrmann R. Cotton A. Bansemer |
| author_facet | S. J. O'Shea J. Crosier J. Crosier J. Dorsey J. Dorsey W. Schledewitz I. Crawford S. Borrmann S. Borrmann R. Cotton A. Bansemer |
| author_sort | S. J. O'Shea |
| collection | DOAJ |
| container_title | Atmospheric Measurement Techniques |
| description | <p>In situ observations from research aircraft and instrumented
ground sites are important contributions to developing our collective
understanding of clouds and are used to inform and validate numerical
weather and climate models. Unfortunately, biases in these datasets may be
present, which can limit their value. In this paper, we discuss artefacts
which may bias data from a widely used family of instrumentation in the field
of cloud physics, optical array probes (OAPs). Using laboratory and synthetic
datasets, we demonstrate how greyscale analysis can be used to filter data,
constraining the sample volume of the OAP and improving data quality,
particularly at small sizes where OAP data are considered unreliable. We
apply the new methodology to ambient data from two contrasting case studies:
one warm cloud and one cirrus cloud. In both cases the new methodology
reduces the concentration of small particles (<60 <span class="inline-formula">µ</span>m) by
approximately an order of magnitude. This significantly improves agreement
with a Mie-scattering spectrometer for the liquid case and with a holographic
imaging probe for the cirrus case. Based on these results, we make specific
recommendations to instrument manufacturers, instrument operators and data
processors about the optimal use of greyscale OAPs. The data from monoscale
OAPs are unreliable and should not be used for particle diameters below
approximately 100 <span class="inline-formula">µ</span>m.</p> |
| format | Article |
| id | doaj-art-e0e6f4c54e4f45ebbbd26de87e63f310 |
| institution | Directory of Open Access Journals |
| issn | 1867-1381 1867-8548 |
| language | English |
| publishDate | 2019-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| spelling | doaj-art-e0e6f4c54e4f45ebbbd26de87e63f3102025-08-19T21:04:04ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482019-06-01123067307910.5194/amt-12-3067-2019Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic dataS. J. O'Shea0J. Crosier1J. Crosier2J. Dorsey3J. Dorsey4W. Schledewitz5I. Crawford6S. Borrmann7S. Borrmann8R. Cotton9A. Bansemer10School of Earth and Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth and Environmental Sciences, University of Manchester, Manchester, UKNational Centre for Atmospheric Science, University of Manchester, Manchester, UKSchool of Earth and Environmental Sciences, University of Manchester, Manchester, UKNational Centre for Atmospheric Science, University of Manchester, Manchester, UKSchool of Earth and Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth and Environmental Sciences, University of Manchester, Manchester, UKParticle Chemistry Department, Max Planck Institute for Chemistry, Mainz, GermanyInstitute for Atmospheric Physics, Johannes Gutenberg University, Mainz, GermanyMet Office, Exeter, UKNational Center for Atmospheric Research, Boulder, CO, USA<p>In situ observations from research aircraft and instrumented ground sites are important contributions to developing our collective understanding of clouds and are used to inform and validate numerical weather and climate models. Unfortunately, biases in these datasets may be present, which can limit their value. In this paper, we discuss artefacts which may bias data from a widely used family of instrumentation in the field of cloud physics, optical array probes (OAPs). Using laboratory and synthetic datasets, we demonstrate how greyscale analysis can be used to filter data, constraining the sample volume of the OAP and improving data quality, particularly at small sizes where OAP data are considered unreliable. We apply the new methodology to ambient data from two contrasting case studies: one warm cloud and one cirrus cloud. In both cases the new methodology reduces the concentration of small particles (<60 <span class="inline-formula">µ</span>m) by approximately an order of magnitude. This significantly improves agreement with a Mie-scattering spectrometer for the liquid case and with a holographic imaging probe for the cirrus case. Based on these results, we make specific recommendations to instrument manufacturers, instrument operators and data processors about the optimal use of greyscale OAPs. The data from monoscale OAPs are unreliable and should not be used for particle diameters below approximately 100 <span class="inline-formula">µ</span>m.</p>https://www.atmos-meas-tech.net/12/3067/2019/amt-12-3067-2019.pdf |
| spellingShingle | S. J. O'Shea J. Crosier J. Crosier J. Dorsey J. Dorsey W. Schledewitz I. Crawford S. Borrmann S. Borrmann R. Cotton A. Bansemer Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data |
| title | Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data |
| title_full | Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data |
| title_fullStr | Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data |
| title_full_unstemmed | Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data |
| title_short | Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data |
| title_sort | revisiting particle sizing using greyscale optical array probes evaluation using laboratory experiments and synthetic data |
| url | https://www.atmos-meas-tech.net/12/3067/2019/amt-12-3067-2019.pdf |
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