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...

Full description

Bibliographic Details
Main Authors:	S. J. O'Shea, J. Crosier, J. Dorsey, W. Schledewitz, I. Crawford, S. Borrmann, R. Cotton, A. Bansemer
Format:	Article
Language:	English
Published:	Copernicus Publications 2019-06-01
Series:	Atmospheric Measurement Techniques
Online Access:	https://www.atmos-meas-tech.net/12/3067/2019/amt-12-3067-2019.pdf

id	doaj-e0e6f4c54e4f45ebbbd26de87e63f310
record_format	Article
spelling	doaj-e0e6f4c54e4f45ebbbd26de87e63f3102020-11-25T00:29:05ZengCopernicus 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
collection	DOAJ
language	English
format	Article
sources	DOAJ
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
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 Atmospheric Measurement Techniques
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
title	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_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_sort	revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data
publisher	Copernicus Publications
series	Atmospheric Measurement Techniques
issn	1867-1381 1867-8548
publishDate	2019-06-01
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>
url	https://www.atmos-meas-tech.net/12/3067/2019/amt-12-3067-2019.pdf
work_keys_str_mv	AT sjoshea revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT jcrosier revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT jcrosier revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT jdorsey revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT jdorsey revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT wschledewitz revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT icrawford revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT sborrmann revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT sborrmann revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT rcotton revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata AT abansemer revisitingparticlesizingusinggreyscaleopticalarrayprobesevaluationusinglaboratoryexperimentsandsyntheticdata
_version_	1725333468229926912

Revisiting particle sizing using greyscale optical array probes: evaluation using laboratory experiments and synthetic data

Similar Items