WMOD00590

• Title: Analysis and Classification of Mesoscale Cloud and Precipitation Systems
• Date: 8/1/1983
• Weather Modification - Doc Type: Report

of Reclamation and the National Science Foundation to better understand
the complex dynamics, thermodynamics and microphysical mechanisms of
convective precipitation evolution. The purpose of this dissertation
is to develop a better understanding of the physical structure of meso-
scale convective triggering mechanisms that produce rainfall and to
stratify precipitation events into more homogeneous classes. To achieve
this, an automated objective analysis technique, graphical display sys-
tem and numerical model were used to describe kinematic and thermody-
namic properties of precipitation events. The technique will be useful
for analysis of the CCOPE data sets to better understand mesoscale
characteristics of convective storms.

In order to test the technique, a set of hypotheses of kinematic
and thermodynamic characteristics of the four classes of precipitation
events was proposed. Then, all 1979 Texas HIPLEX events were stratified
using visible and infrared geosynchronous satellite photographs.
Thermodynamic and kinematic analyses of rawinsonde data were performed
and temporal and spatial characteristics of mesoscale features were
described. Rain gage, radar echo, and satellite-observed cloud charac-
teristics were also analyzed and combined with the thermodynamic results
to provide a comprehensive description of each precipitation class and
its natural variability.

1.1 Problem definition

Extremely large natural variations in convective rainfall from
mesoscale thunderstorms are observed in apparently heterogeneous samples
of mesoscale forcing. Such heterogeneous samples make it difficult to
plan, organize, conduct and evaluate weather modification experiments.
2