Optical Properties of Blowing Snow

AbstractCalculation procedures are developed and results shown for the exact calculation of extinction and meteorological visual range using the blowing-snow mass in the atmosphere and particle radius. Results of the calculations show: (1) For monochromatic radiation, geometrical optics approximations of the extinction efficiency are found to provide results of only moderate accuracy in calculating the extinction of radiation by a single particle. (2) For broad-band radiation, the geometrical optics approximation is sufficiently accurate for many single-particle measurement instruments and applications, except in the infra-red band where Mie theory should be used. (3) For typical blowing-snow particle-size distributions, the shape parameter of the distribution of particle radii and the mean particle radius are very important in broad-band extinction and visual-range modelling. Estimates of blowing-snow quantities from broad-band extinction measurements or visual range from blowing-snow quantities should address the shape and mean value of the snow-particle radius distribution.

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Optical Properties of Blowing Snow

Journal of Glaciology ◽

10.1017/s0022143000008996 ◽

1988 ◽

Vol 34 (116) ◽

pp. 3-10 ◽

Cited By ~ 13

Author(s):

J.W. Pomeroy ◽

D.H. Male

Keyword(s):

Single Particle ◽

Broad Band ◽

Geometrical Optics ◽

Mean Value ◽

Particle Radius ◽

Blowing Snow ◽

Measurement Instruments ◽

Particle Measurement ◽

Snow Particle ◽

Visual Range

Abstract Calculation procedures are developed and results shown for the exact calculation of extinction and meteorological visual range using the blowing-snow mass in the atmosphere and particle radius. Results of the calculations show: (1) For monochromatic radiation, geometrical optics approximations of the extinction efficiency are found to provide results of only moderate accuracy in calculating the extinction of radiation by a single particle. (2) For broad-band radiation, the geometrical optics approximation is sufficiently accurate for many single-particle measurement instruments and applications, except in the infra-red band where Mie theory should be used. (3) For typical blowing-snow particle-size distributions, the shape parameter of the distribution of particle radii and the mean particle radius are very important in broad-band extinction and visual-range modelling. Estimates of blowing-snow quantities from broad-band extinction measurements or visual range from blowing-snow quantities should address the shape and mean value of the snow-particle radius distribution.

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Online single particle measurement of fireworks pollution during Chinese New Year in Nanning

Journal of Environmental Sciences ◽

10.1016/j.jes.2016.04.021 ◽

2017 ◽

Vol 53 ◽

pp. 184-195 ◽

Cited By ~ 19

Author(s):

Jingyan Li ◽

Tingting Xu ◽

Xiaohui Lu ◽

Hong Chen ◽

Sergey A. Nizkorodov ◽

...

Keyword(s):

Single Particle ◽

Particle Measurement ◽

Single Particle Measurement

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Field test of a new snow-particle counter (SPC) system

Annals of Glaciology ◽

10.3189/s0260305500011411 ◽

1993 ◽

Vol 18 ◽

pp. 149-154 ◽

Cited By ~ 18

Author(s):

Takeshi Sato ◽

Tadashi Kimura ◽

Taminoe Ishimaru ◽

Toshisuke Maruyama

Keyword(s):

Wind Speed ◽

Mass Flux ◽

Particle Trajectory ◽

Particle Diameter ◽

Blowing Snow ◽

Fraunhofer Diffraction ◽

Wind Speed Profile ◽

Particle Counter ◽

Sampling Volume ◽

Snow Particle

The optical system of the snow-particle counter (SPC), which was developed by Schmidt in 1977, has been improved. A laser diode is used as a light source, achieving uniform sensitivity to a blowing snow particle regardless of the location of particle trajectory within a sampling volume. The light entering a slit, which may be affected by a blowing snow particle, is perfectly detected by use of a piano-cylindrical lens and a dual-type photodiode. A signal processor has been developed to get output voltage proportional to the mass flux of blowing snow.From the estimates based on blowing snow characteristics and wind speed profile, the new SPC system can accurately detect all the particles of effective sizes at least at a height above 0.1 m when the wind speed at a height of 1 m is less than 15 m s−1.Considering the Fraunhofer diffraction by both the wire and the particle, the relation between a particle diameter and sensor output of the new SPC system is derived from the calibration with spinning wires.Mass flux obtained with the new SPC system was found to be close to that with a snow trap. The system was operated continuously for at least nine days using two 35 A h lead batteries.

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The Chemical Abundances of the Halo Clusters of the Galaxy

Symposium - International Astronomical Union ◽

10.1017/s0074180900145504 ◽

1978 ◽

Vol 80 ◽

pp. 177-182

Author(s):

R. Canterna ◽

R. A. Schommer

Keyword(s):

Globular Clusters ◽

Broad Band ◽

Mean Value ◽

Red Giants ◽

Galactocentric Distance ◽

Chemical Abundances ◽

Dwarf Spheroidal Galaxies ◽

The Galaxy ◽

Ursa Minor ◽

Metal Abundances

Photometric metal abundances of individual red giants in eight extremely distant halo globular clusters and the Draco and Ursa Minor dwarf spheroidal galaxies have been obtained using the Washington broad-band system, C, M, T1, T2(Canterna 1976). Observations were made at the KPNO 2.1-m and CTIO 1.5-m telescopes. In Table I we list for each system the mean value of [Fe/H], the number of stars observed in each system, n, the Galactocentric distance, RGC, the intrinsic color of the giant branch at the level of the horizontal branch (HB), (B-V)o,g, and the fraction of HB stars bluer than the RR Lyrae gap, fB. Sources for unpublished color-magnitude diagram (CMD) data are: Pal 11 (Canterna and Schommer), Pal 12 (Canterna and Harris), and Ursa Minor (Schommer, Olszewski and Kunkel).

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