A Comparison of In-Cloud Measurements Obtained with Six PMS 2D-C Probes

Gayet, Jean-François; Brown, Philip R. A.; Albers, Frank

doi:10.1175/1520-0426(1993)010<0180:acoicm>2.0.co;2

Cited by 48 publications

(48 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The objective was to de®ne a new automatic pattern recognition algorithm in order to di erentiate the images of small hexagonal columns from those of spherical particles. Our method was validated against actual data obtained during an incloud¯ight of the pre-ICE'89 (International Cirrus Experiment) campaign (Gayet et al, 1990;Gayet et al, 1993). We propose a simple way to approximately determine the volume of the particles and then the liquid or ice water content.…”

Section: Introductionsupporting

confidence: 75%

A statistical analysis for pattern recognition of small cloud particles sampled with a PMS-2DC probe

Fouilloux

Iaquinta²,

Duroure

et al. 1997

Ann Geophysicae

View full text Add to dashboard Cite

Abstract. Although small particles (size between 25 lm and 200 lm) are frequently observed within ice and water clouds, they are not generally used properly for the calculation of structural, optical and microphysical quantities. Actually neither the exact shape nor the phase (ice or water) of these particles is well de®ned since the existing pattern recognition algorithms are only e cient for larger particle sizes. The present study describes a statistical analysis concerning small hexagonal columns and spherical particles sampled with a PMS-2DC probe, and the corresponding images are classi®ed according to the occurrence probability of various pixels arrangements. This approach was ®rst applied to synthetic data generated with a numerical model, including the e ects of di raction at a short distance, and then validated against actual data sets obtained from in-cloud¯ights during the pre-ICE'89 campaign. Our method allows us to di erentiate small hexagonal columns from spherical particles, thus making possible the characterization of the three dimensional shape (and consequently evaluation of the volume) of the particles, and ®nally to compute e.g., the liquid or the ice water content.

show abstract

Section: Introductionsupporting

confidence: 75%

A statistical analysis for pattern recognition of small cloud particles sampled with a PMS-2DC probe

Fouilloux

Iaquinta²,

Duroure

et al. 1997

Ann Geophysicae

View full text Add to dashboard Cite

show abstract

“…The probes show large di erences in particle concentration for the larger sizes, even although measuring closely spaced volumes of the same cloud. The di erences appear to be due to instrumentation problems rather than true cloud di erences (Gayet et al, 1993), and are related particularly to the probe version being used, with the updated 2D2-C version apparently detecting some 50% more images than the original version 2D-C. The second source of concentration measurement problems arises through the poor de®ni-tion of the sampling volume, associated with response time problems.…”

Section: Pms 2d-c Probementioning

confidence: 98%

“…The major one relates to the data handling in di erent probes. Figure 1 shows the size spectra obtained simultaneously from three 2D-C probes mounted close together on the same aircraft during a¯ight in cirrostratus at a temperature of around A35°C (Gayet et al, 1993). The probes show large di erences in particle concentration for the larger sizes, even although measuring closely spaced volumes of the same cloud.…”

Section: Pms 2d-c Probementioning

confidence: 99%

Measurement errors in cirrus cloud microphysical properties

et al. 1998

View full text Add to dashboard Cite

Abstract. The limited accuracy of current cloud microphysics sensors used in cirrus cloud studies imposes limitations on the use of the data to examine the cloud's broadband radiative behaviour, an important element of the global energy balance. We review the limitations of the instruments, PMS probes, most widely used for measuring the microphysical structure of cirrus clouds and show the e ect of these limitations on descriptions of the cloud radiative properties. The analysis is applied to measurements made as part of the European Cloud and Radiation Experiment (EUCREX) to determine mid-latitude cirrus microphysical and radiative properties.

show abstract

“…The major one relates to the data handling in dierent probes. Figure 1 shows the size spectra obtained simultaneously from three 2D-C probes mounted close together on the same aircraft during a¯ight in cirrostratus at a temperature of around A35°C (Gayet et al, 1993). The probes show large dierences in particle concentration for the larger sizes, even although measuring closely spaced volumes of the same cloud.…”

Section: Pms 2d-c Probementioning

confidence: 99%

“…The accuracy and consistency of the 2D-C probes has been examined (Gayet et al, 1993) as part of the ICE/ EUCREX programme to determine cirrus microphysical properties. Although development and use of the 2D-C probe unquestionably represents a great advance in cloud physics instrumentation, inherent probe and data analysis shortcomings limit the conditions under which the data can be relied on.…”

Section: Pms 2d-c Probementioning

confidence: 99%

Measurement errors in cirrus cloud microphysical properties

et al. 1998

View full text Add to dashboard Cite

Abstract. The limited accuracy of current cloud microphysics sensors used in cirrus cloud studies imposes limitations on the use of the data to examine the cloud's broadband radiative behaviour, an important element of the global energy balance. We review the limitations of the instruments, PMS probes, most widely used for measuring the microphysical structure of cirrus clouds and show the eect of these limitations on descriptions of the cloud radiative properties. The analysis is applied to measurements made as part of the European Cloud and Radiation Experiment (EUCREX) to determine mid-latitude cirrus microphysical and radiative properties.

show abstract

A Comparison of In-Cloud Measurements Obtained with Six PMS 2D-C Probes

Cited by 48 publications

References 0 publications

A statistical analysis for pattern recognition of small cloud particles sampled with a PMS-2DC probe

A statistical analysis for pattern recognition of small cloud particles sampled with a PMS-2DC probe

Measurement errors in cirrus cloud microphysical properties

Measurement errors in cirrus cloud microphysical properties

Contact Info

Product

Resources

About