Accession Number:

AD0726995

Title:

Field Test of a Forward Scatter Visibility Meter.

Descriptive Note:

Environmental research papers,

Corporate Author:

AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Report Date:

1971-05-26

Pagination or Media Count:

21.0

Abstract:

Field tests of a forward scatter visibility instrument were carried out in August 1970 at Cutler, Maine. The performance characteristics of the new instrument were examined through comparisons of simultaneous measurements of atmospheric extinction coefficient with a conventional transmissometer and through comparisons with human observations of visibility. During periods of dense coastal advection fog, which restricted visibility to less than one mile, the correlations coefficient between forward scatter and transmissometer measurements was about 0.91 with a standard error of estimate of 26 percent. The disparities between simultaneous measurements were caused primarily by high frequency fluctuations in fog density that were detected by the small volume measurements with the forward scatter instrument, but were smoothed out by the measurements of transmittance over a baseline of 500 ft. Additional comparisons of forward scatter measurements and transmittance measurements in winter snow situations gave results similar to those obtained in fog conditions. Author

Subject Categories:

  • Test Facilities, Equipment and Methods
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE