WMOD00372

• Project Name: High Plains Cooperative Program
• Title: The Design of HIPLEX-1
• Date: 4/1/1979
• Weather Modification - Doc Type: Report

I. INTRODUCTION

HIPLEX - the High Plains Cooperative Program - is the Bureau of
Reclamation's research pf"ogram to develop a practical, scientifically
sound, and socially accE~ptable technology for precipitation management
applicable to summer convective cloud systems over the High Plains
region of the United States. It is a joint effort among the Bureau
of Reclamation and State! and local agencies from the High Plains
region. The Bureau has responsibility for the meteorological tech-
nology development, including hypothesis testing and verification,
seeding system development, and evaluation. The states have accepted
primary responsibility for nonmeteorological technology development,
including impact assessnll=nt, legal and institutional arrangements,
and local decisionmaking criteria.

A major objective of the HIPLEX Program is to identify those condi-
tions when seeding warm..season convective clouds in a prescribed
manner leads to increases, no effect, or decreases in precipitation
and al so the area and md.gnitude of those effects. As the sc ient ific
uncertainties concerning natural and modified processes are reduced,
research will progress from the relatively simple cumulus congestus
to more complex and extensive cloud and mesoscale systems.

HIPLEX-1 is the first in a series of experiments under the High
Plains Cooperative Proglram aimed at establishing the physical basis
for enhancing beneficial growing-season precipitation from convective
clouds in the High Pl ailns. The experiment is focused on small, semi-
isolated cumulus congest us clouds and explores the hypothesis that
both the probability and amount of rainfall can be increased by means
of ice-embryo seeding for microphysical effects. The experiment will
be one in which each step leading to the additional precipitation
development is specified in advance and is verified by observations
in the course of the experiment. This concept represents a return to
the exper imenta 1 approach set forth by Braham and others 2 decades
ago (see, for example, Braham et al., 1957) which is particularly
attractive now because of the recent development of better measurement
capabilities. The statistical-physical analysis will evaluate the
sequential response variables using both univariate and multivariate
methods based on permutation and rerandomization procedures. Independ-
ent but coordinated physical evaluations will be conducted to establish
the cause-effect relationships for any modifications to the cloud and
precipitation processes.

This design document sets forth, prior to the start of the randomized
experiment, descriptions of the hypotheses, the experimental procedures,
and the evaluation techniques for HIPLEX-1. Details and pertinent
support information are presented in the appendixes.

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