WMOD00438

• Title: HIPLEX: A Cooperative Program on Rain Augmentation in the High Plains
• Date: 6/1/1984
• Weather Modification - Doc Type: Report

Table 3.3.-Direct income effect by month and crop due to 10 percent increase in rainfall based
on regional regression models *
(Thousands of dollars)
Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.
Cotton. 176.3 176.3 264.4
Grain Sorghum. 34.1 27.0 56.8 135.5 135.5 118.0
Wheat. 2.0 1.7 2.4 4.7 2.6 2.8 3.5 7.3 3.1 2.;~
TOTAL 212.4 205.0 323.6 4.7 135.5 138. 1 120.8 3.5 7.3 3.1 2.2

* Values based on average acres harvested 1964 - 1973 and on 1967 prices received.

NOTE: Dashes indicate that there was no significant impact of additional rainfall during these months according
to the regression analysis.

Spring-Snyder regional economy would be to
create an overall expansion in regional output of
approximately $ 3.7 million and a similar expan-
sion of regional income of $ 2.3 million.

3.8 Summary

The first 6 years of the Texas HIPLEX Program con-
sisted mostly of exploratory research. i.e.. data
collection and some initial analysis. During the last
years of the Texas HIPLEX Program. increased anal-
ysis efforts were directed to understanding the
mesoscale controls of convective cloud develop-
ment and the microscale properties of cloud and pre-
cipitation processes.

There are four major technical accomplishments of
the Texas HIPLEX Program:

a. Collection of data from a dense network of rain
gages, a surface network. and a mesoscale
rawinsonde network for the southern Plains from
1976 through 1980.

b. Development of objective analysis tools and
their application to the data base in order to
understand the natural controls of rainfall in the
region.

c. Commencement of experimental design to
test effects of seeding on convective rainfall in
west Texas.

d. Economic studies which estimated the impact
of additional water on crop production, ground-
water pumpage, and regional income.

Analysis of rainfall and mesoscale wind fields con-
firmed the dominant roles of lifting and horizontal
moisture convergence in the production of rainfall in
west Texas. Various types of cloud systems produc-
ing rainfall have been identified. and the rainfall sta-
tistics of each type have been determined.

Rawinsonde and surface networks have provided
predictive information that sho"Vs when and where
enhanced clouds and precipitation will develop and
where naturaUy suppressed conditions exist. Hence.
the value of mesoscale observations with real-time
analysis tools to the most effective conduct of
experiments has been established. These data and
analyses should help to determine when and where
to send aircraft to seed clouds and to evaluate seed-
ing effectiveness.

Nevertheless, the termination of HIPLEX left us with
an incomplete picture of processes of precipi-
tation growth. cloud-environment interactions. and
of mesoscale triggering that initiates and maintains
convective systems. Additional analysis and data col-
lection efforts are needed to establish the trans-
ferability to Texas of technology learned in the
microphysical studies in HIPLEX-1 in Montana and
elsewhere.

Plans within the Texas DWR call for the development
of comprehensive hypotheses and a statistical
design for a cloud seeding experiment. which will
provide a sound basis for benefit-to-cost analysis of
freshwater augmentation through operational
weather modification programs.

4. RESULTS OF KANSAS HIPLIEX

4.1 Overview

The Kansas HIPLEX program provided information
regarding the natural structure of convective clouds
and rainfall in the central High Plains. Table 4.1 lists
the participants in the Kansas HIPLEX studies. Figure
4.1 shows the location of this field program and the
SPACE (South Park Area Cumulus Experiment).
SPACE was a cooperative effort between the
Bureau, National Science Foundation. NOAA, and

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