Accession Number : ADA141552

Title :   Investigation of the Detectability and Lifetime of Gust Fronts and Other Weather Hazards to Aircraft.

Descriptive Note : Final rept. Feb 82-Oct 83,

Corporate Author : NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION NORMAN OK NATIONAL SEVERE STORMS LAB

Personal Author(s) : Zrnic,D S ; Lee,J T

PDF Url : ADA141552

Report Date : Oct 1983

Pagination or Media Count : 60

Abstract : Low-altitude wind shear associated with diverging outflows has been related to several aircraft accidents. We examine several gust fronts using Doppler radar data and measurements from surface stations and tall tower. We present radar-derived parameters such as reflectivity, height, maximum shear, peak velocity, distance of the front from the producing storm and the nearest 30 dBZ contour for several gust fronts within 60 km of the radar during 1980 to 1982. For all orientations of the front, even along the radial direction, the forntal discontinuity was evident in both mean velocity and spectrum width fields. Thus, while detection is practical with a single Doppler radar, accurate estimation of shear magnitudes is more difficult when the frontal discontinuity is aligned along the radial. Several downdrafts of different sizes are present simultaneously behind some of the fronts and the maximum measured shear of radial velocities produced by one downdraft was .02/s. A more typical value of 100/s was observed at several locations. Maximum azimuthal shear of 470/s occurred at the wave crest.

Descriptors :   *Gusts, *Fronts(Meteorology), Thunderstorms, Radar reflections, Meteorological radar, Doppler radar, Wind velocity, Wind shear, Measurement, Oklahoma

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE