Elliptical storm cell modeling of digital radar data

Abstract

A model for spatial distributions of reflectivity in storm cells was fitted to digital radar data. The data were taken with a modified WSR-57 weather radar with 2.6-km resolution. The data consisted of modified B-scan records on magnetic tape of storm cells tracked at 0 deg elevation for several hours. The MIT L-band radar with 0.8-km resolution produced cross-section data on several cells at 1/2 deg elevation intervals. The model developed uses ellipses for contours of constant effective-reflectivity factor Z with constant orientation and eccentricity within a horizontal cell cross section at a given time and elevation. The centers of the ellipses are assumed to be uniformly spaced on a straight line, with areas linearly related to log Z. All cross sections are similar at different heights (except for cell tops, bottoms, and splitting cells), especially for the highest reflectivities; wind shear causes some translation and rotation between levels. Goodness-of-fit measures and parameters of interest for 204 ellipses are considered.