ATTENUATION OF VISIBLE LIGHT BY FALLING SNOW
THE ATTENUATION OF VISIBLE LIGHT BY FALLING SNOW WAS STUDIED BY MAKING SIMULTANEOUS ATTENUATION MEASUREMENTS AND SNOW CONCENTRATION MEASUREMENTS. THE ATTENUATION COEFFICIENT WAS CALCULATED FROM PHOTOMETRIC MEASUREMENTS AND FROM VISUAL OBSERVATIONS. THE SNOWFLAKES WERE ARBITRARILY CLASSIFIED BY CRYSTAL TYPES ACCORDING TO THEIR ESTIMATED FALL VELOCITY. IT WAS FOUND THAT THE CORRELATION BETWEEN EXTINCTION COEFFICIENT (ATTENUATION) AND SNOW CONCENTRATION WAS GENERALLY MUCH HIGHER BY TYPES THAN WHEN ALL SNOWFLAKES WERE CONSIDERED TOGETHER REGARDLESS OF CRYSTAL COMPONENTS AND DEGREE OF TIMING. WHEN NO FOG IS PRESENT DURING THE SNOWFALL, THE EXPERIMENTAL RESULTS COINCIDE WELL WITH ATTENUATION THEORY IF A REASONABLE CORRECTION IS APPLIED TO THE VALUES OBTAINED IN THE MEASUREMENT OF SNOWFLAKE DIAMETERS. MEASUREMENTS OF MASS FLUX INDICATE THAT FOR A GIVEN INTENSITY THE ATTENUATION CAUSED BY SNOW IS AN ORDER OF MAGNITUDE GREATER THAN THAT CAUSED BY THE SAME MASS FLUX OF RAIN. /AUTHOR/
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Supplemental Notes:
- No 242, 31 PP
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Authors:
- Obrien, H W
- Publication Date: 1969-6
Media Info
Subject/Index Terms
- TRT Terms: Concentration (Chemistry); Fog; Light; Measurement; Rainfall; Snow
- Uncontrolled Terms: Attenuation; Concentration
- Subject Areas: Highways; Safety and Human Factors;
Filing Info
- Accession Number: 00220631
- Record Type: Publication
- Files: TRIS
- Created Date: Jan 19 1970 12:00AM