Accession Number:

ADA179176

Title:

Otis ANGB (Air National Guard Base) Visibility Sensor Field Test Study.

Descriptive Note:

Final rept. Dec 83-Jan 86,

Corporate Author:

TRANSPORTATION SYSTEMS CENTER CAMBRIDGE MA

Personal Author(s):

Report Date:

1987-02-01

Pagination or Media Count:

186.0

Abstract:

This study is part of a continuing effort to evaluate forward scatter meters FSMs for use as visibility sensors in Automatic Observing Systems AOS and as possible replacements for transmissometers to measure Runway Visual Range RVR at airports. The report analyzes data collected from three FSMs at the Otis Air National Guard Base during a 17-month period starting in 1983. Two of the FSMs use chopped incandescent light sources and have a large scatter volume. The other uses a modulated light emitting diode LED light source and has a small scatter volume. Two analysis procedures are included 1 a statistical analysis of the entire data set disaggregated according to the obstruction to vision fog, rain, snow, etc. and the magnitude of the extinction coefficient and 2 detailed analysis of selected reduced visibility events. Most of the time extinction coefficients measured by the FSMs and the transmissometers agreed to within 16.5 percent for RVR values between 400 and 6000 feet and within one reporting increment for AOS visibility. Most of the cases of large disagreement were traced to problems such as sensors being clogged by snow, which affected both FSMs and the transmissometers. In terms of operational utility, the large volume FSMs gave more stable readings, but the FSM with the LED light source exhibited less calibration drift and greater reliability. Author

Subject Categories:

  • Meteorology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE