WMOD00544

• Project Name: Project Skywater
• Title: Project Skywater - An Introduction to Rivers in the Sky
• Date: 12/1/1973
• Weather Modification - Doc Type: Report

was learned about nature's rainfall proc-
esses and how they might be modified in
western Kansas, the project leaders
agreed more detailed studies and field ex-
periments are necessary.

The three operational projects (Texas,
Oklahoma, and Arizona drought relief)
were of an emergency nature, and time
did not permit an elaborate, scientific
evaluation. Cloud seeding research proj-
ects leave some seedable clouds unseeded
so they can be compared with seeded
.clouds and the effects of the seeding can
thus be determined. However, in these
three projects the need for water dictated
the seeding of all suitable clouds. Data
from radar and measured rainfall amounts
were compared with numerical model pre-
dictions and with past projects that seeded
similar-type clouds. The total precipita-
tion was increased by an estimated 10 to
15 percent over what would have normally
occurred under drought conditions through
the duration of the drought-relief pro-
grams.

In each drought-relief program, the
weather changed from dry to rainy about
the time cloud seeding began. Much of
the substantial drought relief can be at-
tributed to natural processes. What share
of the rain resulted from the application
of cloud seeding technology is a question
that cannot be answered precisely. Mete-
orologists who observed the operations
were excited by what appeared to be fre-
quently successful seedings. One thing
can be said with confidence: It rained!

Small particle size is important

in applying hygroscopic seeding

techniques. Tiny jets emitting

from 0.0135 inch holes in plastic

pipe impinge to produce spray.

17