Accession Number : AD0622861

Title :   RADAR FORECASTING OF VISIBILITY RESTRICTIONS IN SNOW.

Descriptive Note : Interim rept.,

Corporate Author : TRAVELERS RESEARCH CENTER INC HARTFORD CT

Personal Author(s) : Wilson, James W.

Report Date : SEP 1965

Pagination or Media Count : 30

Abstract : Quantitative echo-intensity data from two snowstorms, collected with the WSR-57 at Washington, D. C., are compared with visual-range data from 7 transmissometers located within 45 miles of the radar. In general, a high correlation exists between average radar received power and runway visual range; the coefficient of correlation exceeds 0.82 for stations within 35 miles of the radar during periods of significant changes in visual range. The relationship between visual range (V) and average radar-received power (P sub r) is of the form log V = AP sub r - B, where A and B are constants. 10- to 70minute forecasts of visual range are obtained by extrapolating the radar echo pattern and converting the resulting echo intensities, by the above relationship, to visual range. Comparison of radar and persistence forecasts of visual range indicates that the radar forecasts are generally superior. Although further tests are required before weather radar can be recommended for operational use in visual-range forecasting, the possibilities look promising. (Author)

Descriptors :   *ALL WEATHER AVIATION, *WEATHER FORECASTING, *METEOROLOGICAL RADAR, SNOW, RUNWAYS, VISIBILITY, RADAR SCANNING, RADAR CROSS SECTIONS, ATMOSPHERIC PRECIPITATION, CORRELATION TECHNIQUES, CIVIL AVIATION.

Subject Categories : Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE