Wright, P. D. | Search NASA

NASA NTRS1991

A multiparameter radar examination of a mesoscale convective system

Differences in the rainrates of various cells embedded within a mesoscale convective system on July 13, 1986 during the Cooperative Huntsville Meteorological experiment are examined. The NCAR CP2 S-band polarimetric radar deployed near Huntsville, Alabama, is used to characterize the rainfall field. Rainfall estimates are compared and contrasted using the single-parameter Marshall and Palmer (1948) method with the Illingworth and Caylor (1989) dual-polarization technique (ILC). The primary differences in the rainrate estimates are shown to be associated with the differences in the drop size distributions, derived from the ILC technique, that occur within the various storms.

Wright, P. D.↗

NASA NTRS1990

Lightning/rainfall relationships during COHMEX

Initial results of relationships between cloud-to-ground lightning and radar-derived precipitation measurements in air mass thunderstorms (multi- and single cell) occurring over the Southeastern United States are presented. Buoyancy values computed from soundings are used to estimate wind shear, the energy available to storms, and the ability of the environment to support strong updrafts. Precipitation measurements are utilized for sampling the rainfall history of entire storm life cycles. It is shown that the average rain volume per ground discharge decreases as the buoyancy increases; this is attributed to stronger updrafts elevating mass to higher levels in the storm where more frequent ice particle interactions may play a major role in separating charge leading to enhanced lightning activity. Thus, total lightning rates are expected to correlate better with rainfall production.

Goodman, S. J.↗