Abstract
An airborne holographic system developed by the Meteorological Research Flight in Farnborough, England, is described. This system was employed during the International Cirrus Experiment in 1989. Ice particle concentration, size and shape were determined in three height levels in cirrus clouds and assigned to the surrounding temperature and humidity. Most of the particles were found to be smaller than 100 {mu}m. Hexagonal columns, bullets, particles of irregular shape and only a few hexagonal plates were detected. Nearly all particles larger than 200 {mu}m showed a complex internal structure. Most of them were bullet rosettes and combinations of columns. Only one rimed column and one frozen big drop were found in the sampled data. The limitations and uncertainties of the holographic system were investigated and proposals for improvements are made. An improved system would be able to collect images of particles as small as 20 {mu}m and to determine their concentration and size. The development of a proposed new holographic system should be able to detect particles as small as 8 {mu}m. The very labour-intensive data extraction process outlines the need for the development of an automatic image analysing system, which is also discussed. (orig.). 120 figs., 13 tabs. [Deutsch] In
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Citation Formats
Krupp, C.
Holographic measurements on ice particles in cirrus clouds during the international cirrus experiment in 1989; Holographische Messungen an Eiskristallen in Cirruswolken waehrend des Internationalen Cirrus Experiments ICE.
Germany: N. p.,
1992.
Web.
Krupp, C.
Holographic measurements on ice particles in cirrus clouds during the international cirrus experiment in 1989; Holographische Messungen an Eiskristallen in Cirruswolken waehrend des Internationalen Cirrus Experiments ICE.
Germany.
Krupp, C.
1992.
"Holographic measurements on ice particles in cirrus clouds during the international cirrus experiment in 1989; Holographische Messungen an Eiskristallen in Cirruswolken waehrend des Internationalen Cirrus Experiments ICE."
Germany.
@misc{etde_10122350,
title = {Holographic measurements on ice particles in cirrus clouds during the international cirrus experiment in 1989; Holographische Messungen an Eiskristallen in Cirruswolken waehrend des Internationalen Cirrus Experiments ICE}
author = {Krupp, C}
abstractNote = {An airborne holographic system developed by the Meteorological Research Flight in Farnborough, England, is described. This system was employed during the International Cirrus Experiment in 1989. Ice particle concentration, size and shape were determined in three height levels in cirrus clouds and assigned to the surrounding temperature and humidity. Most of the particles were found to be smaller than 100 {mu}m. Hexagonal columns, bullets, particles of irregular shape and only a few hexagonal plates were detected. Nearly all particles larger than 200 {mu}m showed a complex internal structure. Most of them were bullet rosettes and combinations of columns. Only one rimed column and one frozen big drop were found in the sampled data. The limitations and uncertainties of the holographic system were investigated and proposals for improvements are made. An improved system would be able to collect images of particles as small as 20 {mu}m and to determine their concentration and size. The development of a proposed new holographic system should be able to detect particles as small as 8 {mu}m. The very labour-intensive data extraction process outlines the need for the development of an automatic image analysing system, which is also discussed. (orig.). 120 figs., 13 tabs. [Deutsch] In der vorliegenden Arbeit wird ein flugzeuggetragenes, holographisches System zur Aufnahme von Wolkenpartikeln beschrieben, das in einer Abteilung der englischen Meteorological Office, dem Meteorological Research Flight in Farnborough, England, entwickelt wurde und waehrend des Internationalen Cirrus Experiments 1989 zum Einsatz kam. Anzahldichte, Groesse und Form von Eiskristallen in drei verschiedenen Flugniveaus in Cirruswolken wurden ermittelt und in Zusammenhang mit der umgebenden Temperatur und Feuchte gebracht. In allen drei Flugniveaus sind Partikel, die kleiner als 100 {mu}m sind, vorherrschend. Hexagonale Saeulen, Prismen, irregulaere Kristallformen und einige wenige Platten werden nachgewiesen. Fast alle Partikel, die groesser als 200 {mu}m sind, weisen eine zum Teil komplexe interne Struktur auf. Es handelt sich dabei vorwiegend um Flaschenprismenbueschel und Kombinationen von Saeulen, aber auch eine verreifte Saeule und ein gefrorener grosser Tropfen wurden gefunden. Das holographische Verfahren wird auf seine Grenzen und Fehler hin untersucht und es werden Vorschlaege formuliert, die es erlauben sollten, durch eine Verbesserung des bestehenden Systems Partikel bis hinunter zu einer Groesse von 20 {mu}m abzubilden und ihre Anzahldichte zuverlaessig zu bestimmen. Durch die Entwicklung eines neuen Systems liessen sich Partikel bis hinunter zu 8 {mu}m aufnehmen. Da die Hologrammauswertung ausserordentlich arbeitsintensiv ist, werden die Moeglichkeiten einer Automatisierung dargestellt. (orig.)}
place = {Germany}
year = {1992}
month = {Dec}
}
title = {Holographic measurements on ice particles in cirrus clouds during the international cirrus experiment in 1989; Holographische Messungen an Eiskristallen in Cirruswolken waehrend des Internationalen Cirrus Experiments ICE}
author = {Krupp, C}
abstractNote = {An airborne holographic system developed by the Meteorological Research Flight in Farnborough, England, is described. This system was employed during the International Cirrus Experiment in 1989. Ice particle concentration, size and shape were determined in three height levels in cirrus clouds and assigned to the surrounding temperature and humidity. Most of the particles were found to be smaller than 100 {mu}m. Hexagonal columns, bullets, particles of irregular shape and only a few hexagonal plates were detected. Nearly all particles larger than 200 {mu}m showed a complex internal structure. Most of them were bullet rosettes and combinations of columns. Only one rimed column and one frozen big drop were found in the sampled data. The limitations and uncertainties of the holographic system were investigated and proposals for improvements are made. An improved system would be able to collect images of particles as small as 20 {mu}m and to determine their concentration and size. The development of a proposed new holographic system should be able to detect particles as small as 8 {mu}m. The very labour-intensive data extraction process outlines the need for the development of an automatic image analysing system, which is also discussed. (orig.). 120 figs., 13 tabs. [Deutsch] In der vorliegenden Arbeit wird ein flugzeuggetragenes, holographisches System zur Aufnahme von Wolkenpartikeln beschrieben, das in einer Abteilung der englischen Meteorological Office, dem Meteorological Research Flight in Farnborough, England, entwickelt wurde und waehrend des Internationalen Cirrus Experiments 1989 zum Einsatz kam. Anzahldichte, Groesse und Form von Eiskristallen in drei verschiedenen Flugniveaus in Cirruswolken wurden ermittelt und in Zusammenhang mit der umgebenden Temperatur und Feuchte gebracht. In allen drei Flugniveaus sind Partikel, die kleiner als 100 {mu}m sind, vorherrschend. Hexagonale Saeulen, Prismen, irregulaere Kristallformen und einige wenige Platten werden nachgewiesen. Fast alle Partikel, die groesser als 200 {mu}m sind, weisen eine zum Teil komplexe interne Struktur auf. Es handelt sich dabei vorwiegend um Flaschenprismenbueschel und Kombinationen von Saeulen, aber auch eine verreifte Saeule und ein gefrorener grosser Tropfen wurden gefunden. Das holographische Verfahren wird auf seine Grenzen und Fehler hin untersucht und es werden Vorschlaege formuliert, die es erlauben sollten, durch eine Verbesserung des bestehenden Systems Partikel bis hinunter zu einer Groesse von 20 {mu}m abzubilden und ihre Anzahldichte zuverlaessig zu bestimmen. Durch die Entwicklung eines neuen Systems liessen sich Partikel bis hinunter zu 8 {mu}m aufnehmen. Da die Hologrammauswertung ausserordentlich arbeitsintensiv ist, werden die Moeglichkeiten einer Automatisierung dargestellt. (orig.)}
place = {Germany}
year = {1992}
month = {Dec}
}