Depolarization ratios of single ice particles assuming finite circular cylinders

2007 ◽  
Vol 46 (20) ◽  
pp. 4465 ◽  
Author(s):  
Mathieu Nicolet ◽  
Olaf Stetzer ◽  
Ulrike Lohmann
Keyword(s):  
Circular Cylinders ◽  
Ice Particles ◽  
Depolarization Ratios

scholarly journals Circular depolarization ratios of single water droplets and finite ice circular cylinders: a modeling study

2012 ◽  
Vol 12 (9) ◽  
pp. 4207-4214 ◽  
Author(s):  
M. Nicolet ◽  
M. Schnaiter ◽  
O. Stetzer
Keyword(s):  
Polarized Light ◽  
Ice Crystals ◽  
Particle Orientation ◽  
Circular Cylinders ◽  
Cylindrical Shape ◽  
Water Droplets ◽  
Particle Detection ◽  
Phase Discrimination ◽  
The Difference ◽  
Depolarization Ratios

Abstract. Computations of the phase matrix elements for single water droplets and ice crystals in fixed orientations are presented to determine if circular depolarization δC is more accurate than linear depolarization for phase discrimination. T-matrix simulations were performed to calculate right-handed and left-handed circular depolarization ratios δ+C, respectively δ−C and to compare them with linear ones. Ice crystals are assumed to have a circular cylindrical shape where their surface-equivalent diameters range up to 5 μm. The circular depolarization ratios of ice particles were generally higher than linear depolarization and depended mostly on the particle orientation as well as their sizes. The fraction of non-detectable ice crystals (δ<0.05) was smaller considering a circular polarized light source, reaching 4.5%. However, water droplets also depolarized light circularly for scattering angles smaller than 179° and size parameters smaller than 6 at side- and backscattering regions. Differentiation between ice crystals and water droplets might be difficult for experiments performed at backscattering angles which deviate from 180° unlike LIDAR applications. Instruments exploiting the difference in the P44/P11 ratio at a scattering angle around 115° are significantly constrained in distinguishing between water and ice because small droplets with size parameters between 5 and 10 do cause very high circular depolarizations at this angle. If the absence of the liquid phase is confirmed, the use of circular depolarization in single particle detection is more sensitive and less affected by particle orientation.

scholarly journals Experimental assessment of the lidar polarizing sensitivity

2016 ◽  
Author(s):  
L. Belegante ◽  
J. A. Bravo-Aranda ◽  
V. Freudenthaler ◽  
D. Nicolae ◽  
A. Nemuc ◽  
...  
Keyword(s):  
Mass Concentration ◽  
Depolarization Ratio ◽  
Lidar System ◽  
Experimental Assessment ◽  
Ice Particles ◽  
Lidar Measurements ◽  
Extended Analysis ◽  
532 Nm ◽  
Main Factor ◽  
Depolarization Ratios

Abstract. Particle depolarization ratio retrieved from lidar measurements are commonly used for aerosol typing studies, microphysical inversion, or mass concentration retrievals. The particle depolarization ratio is one of the primary parameters that can differentiate several major aerosol components, but only if the measurements are accurate enough. The uncertainties related to the retrieval of particle depolarization ratios are the main factor in determining the accuracy of the derived parameters in such studies. This paper presents an extended analysis of different depolarization calibration procedures, in order to reduce the related uncertainties. The calibration procedures are specific to each lidar system of the European Aerosol Research Lidar Network – EARLINET with polarising capabilities. The results illustrate a significant improvement of the depolarization lidar products for all the selected lidar stations. The calibrated volume and particle depolarization profiles at 532 nm show values that agree with the theory for all selected atmospheric constituents (several aerosol species, ice particles and molecules in the aerosol free regions).

scholarly journals Circular depolarization ratios of single water droplets and finite ice circular cylinders: a modeling study

2011 ◽  
Vol 11 (11) ◽  
pp. 30125-30144
Author(s):  
M. Nicolet ◽  
M. Schnaiter ◽  
O. Stetzer
Keyword(s):  
Polarized Light ◽  
Ice Crystals ◽  
Particle Orientation ◽  
Circular Cylinders ◽  
Cylindrical Shape ◽  
Water Droplets ◽  
Particle Detection ◽  
Phase Discrimination ◽  
Single Particle Detection ◽  
Depolarization Ratios

Abstract. Computations of the phase matrix elements for single water droplets and ice crystals in fixed orientations are presented to determine if circular depolarization δ&amp;pm;C is more accurate than linear depolarization for phase discrimination. T-matrix simulations were performed to calculate right-handed and left-handed circular depolarization ratios δ&amp;plus;C, respectively δ−C and to compare them with linear ones. Ice crystals are assumed to have a circular cylindrical shape where their surface-equivalent diameters range up to 5 μm. The circular depolarization ratios of ice particles were generally higher than linear depolarization and depended mostly on the particle orientation as well as their sizes. The fraction of non-detectable ice crystals (δ < 0.05) was smaller considering a circular polarized light source, reaching 4.5%. However, water droplets also depolarized light circularly for scattering angles smaller than 179° and size parameters smaller than 6 at side- and backscattering regions. Differentiation between ice crystals and water droplets might be difficult for experiments performing at backscattering angles which deviate from 180° unlike lidar applications. If the absence of the liquid phase is confirmed, the use of circular depolarization in single particle detection is more sensitive and less affected by particle orientation.

Spectral and depolarization ratios for atmospheric ice particles of hexagonal and arbitrary shape within the framework of the physical optics and discrete dipoles

2021 ◽  
Author(s):  
Nikolay G. Bulakhov ◽  
Alexander V. Konoshonkin ◽  
Ilya V. Tkachev ◽  
Dmitriy N. Timofeev ◽  
Victor A. Shishko ◽  
...  
Keyword(s):  
Arbitrary Shape ◽  
Physical Optics ◽  
Ice Particles ◽  
Depolarization Ratios

Numerical Investigation of Flow and Heat Transfer around Two Semi-Circular Cylinders with a Splitter Plate

2011 ◽  
Vol 42 (7) ◽  
pp. 595-612
Author(s):  
Masome Heidary ◽  
Mousa Farhadi ◽  
Kurosh Sedighi ◽  
Mostafa Nourollahi
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Splitter Plate ◽  
Circular Cylinders ◽  
Flow And Heat Transfer

Unfoldings of the Circular Cylinders Having Non-Competitive Axles

2019 ◽  
Vol 17 (16) ◽  
pp. 52-55
Author(s):  
Carmen Popa ◽  
Violeta Anghelina ◽  
Octavian Munteanu
Keyword(s):  
Classical Method ◽  
Descriptive Geometry ◽  
Circular Cylinders ◽  
Intersection Curve ◽  
Engineering Sciences

Abstract The descriptive geometry constitues the foundation of the engineering sciences, so necessary to the specialists of this field. The aim of this paper is to establish the intersection curve between two cylinders and their unfoldings, by using the programmes:AutoCAD and Mathematica. We used the classical method and we first establish the intersection curve and then the cylinders unfoldings. To do this, we used the AutoCAD program. The same unfoldings can be obtained by introducing directly the curve equations (which are inferred) in Mathematica program.

On Vortex Streets behind Circular Cylinders in Side-by-Side Arrangement

1990 ◽  
Vol 10 (1Supplement) ◽  
pp. 35-40 ◽  
Author(s):  
Kazuo OHMI ◽  
Kensaku IMAICHI ◽  
Ei-ichi TADA
Keyword(s):  
Circular Cylinders ◽  
Vortex Streets
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