Accession Number : AD0727740

Title :   Particulate Diffusion over Irregular Terrain.

Descriptive Note : Technical rept.,

Corporate Author : METRONICS ASSOCIATES INC PALO ALTO CALIF AEROSOL LAB

Personal Author(s) : McMullen,R. W. ; Perkins,W. A.

Report Date : 25 JAN 1963

Pagination or Media Count : 59

Abstract : The results of four nighttime FP tracer field trials involving elevated crosswind line sources over irregular terrain are presented. Release heights varied from 1000 to 2200 feet above terrain at the flight line and were approximately at the same elevation of a downwind ridge line which rose to 6200-6600 ft. msl. In each trial the tracer cloud moved parallel to the main ridge line and crossed the lateral canyons on both sides which were instrumented with sampling and meteorological equipment. The nearest sampling position was 7 miles from the release line; the most distant, 9 to 13 miles, depending on wind direction. Sampling results showed that direct vertical mixing during cloud passage aloft accounted for the major portion of the total FP recovery in spite of inversion conditions within the canyons. Transport of FP in the downslope drainage flow contributed to a lesser extent. The direct mixing is attributed to mechanical turbulence induced by the irregular terrain. (Author)

Descriptors :   (*ATMOSPHERIC MOTION, TRACER STUDIES), (*AEROSOLS, SAMPLING), MOUNTAINS, CLOUDS, NETWORKS, METEOROLOGICAL INSTRUMENTS, UPPER ATMOSPHERE, ATMOSPHERIC SOUNDING, TEST EQUIPMENT

Subject Categories : Atmospheric Physics
      Civil Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE