Applicability of the VisiSize D30 shadowgraph system for cloud microphysical measurements
| Autor: | Jakub L. Nowak, Szymon P. Malinowski, Moein Mohammadi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Atmospheric Science
Materials science 010504 meteorology & atmospheric sciences lcsh:TA715-787 Dispersity lcsh:Earthwork. Foundations Evaporation Mechanics 01 natural sciences Sample (graphics) Sizing 010305 fluids & plasmas lcsh:Environmental engineering Physics::Fluid Dynamics Flow focusing 0103 physical sciences Shadowgraph Depth of field Particle size lcsh:TA170-171 0105 earth and related environmental sciences |
| Zdroj: | Atmospheric Measurement Techniques Atmospheric Measurement Techniques, Vol 14, Pp 2615-2633 (2021) |
| ISSN: | 1867-8548 |
| Popis: | A commercial shadowgraph system, the Oxford Lasers VisiSize D30, originally designed to characterize industrial and agricultural sprays, was tested with respect to its application for measuring cloud microphysical properties such as droplet size distribution and number concentration. A laboratory experiment with a dense stream of polydisperse cloud-like droplets indicated a strong dependence of the depth of field, and thus also the sample volume, on particle size. This relationship was determined and a suitable correction method was developed to improve estimations of droplet number concentration and size distribution. The spatial homogeneity of the detection probability inside the sample volume and the minimum droplet diameter providing uniform detection were examined. A second experiment with monodisperse droplets produced by a Flow Focusing Monodisperse Aerosol Generator (FMAG) verified the sizing accuracy and demonstrated reasonable agreement between the instruments. Effects of collisions and the evaporation of droplets produced by the FMAG were observed. Finally, when the instrument was applied to sample atmospheric clouds at a mountain-based observatory, it performed reliably during a 3-week-long field experiment. Based on the laboratory and field tests, recommendations concerning the use of the instrument for cloud droplet measurements were formulated. |
| Databáze: | OpenAIRE |
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