WMOD00590

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

Therefore, the goal of this researcn 1S to understand the factors that

contribute to natural T,esoscale heterogeneities which produce large

variations in rainfall and, thus, enable us to select more homogeneous

samples within which seeding effects may be detected and measured.

Orlanski (1975) has designated the a, ;S,vscales as those required

to define phenomena having subsynoptic size. These scales are defined

in terms of the system wavelength ~ and time scales as:

Me so a
Meso ;3
t'~eso y

250 < L < 2500 km
25 < L < 250 km
2.5 < L < 25 km

6 < t < 36 h
l<t<6h
o.T < t < 1 h

These definitions are used throughout this report.

Previous weather modification field experiments ~ave failed to

recognize the need for mesoscale rawinsonde observations and the physi-

cal understanding of mesoscale triggering effects on convective precipi-

tation. Therefore, the Texas HIPLEX data set represents a unique source

of information that provides digital radar, rain gage, rawinsonde and

satellite observations (e.g., Riggio et al., 1982). Fig. 1.1 shows the

location and scale of observations in this experi~ent. Sy~optic and

meso-p scale rawinsonde n~tworks and radar site are shown on the two-

degree grid of the objective analyses. A critical problem in mesoscale

analysis is the automated analysis of mesoscale features and quantita-

tive prediction of the mesoscale triggering effects on cloud development

and precipitation. Anthes et al. (1982) have shown the value of meso-

scale analyses in fine-mesh models to predict mesoscale regions of

severe storm development. This study provides a unique analysis tech-

nique that uses mesoscale objective analyses of vertical motion fields

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