WMOD00137

• Applicant: J. William Bullock
• Project Name: E. of Colorado Springs Research Project
• Date: 3/15/1978
• Weather Modification - Doc Type: Report

ABSTRACT

An investigation is made into the prospects for

nucleating widespread ice particle clouds in clear air

for the purpose of moderating surface temperature extremes

and modulating atmospheric convection. using aircraft con-

trails as a model, it appears that on many occasions ice

particle clouds can be nucleated in clear areas of the

upper troposphere that will decrease incoming solar radia-

tion by 10% and that will decrease the outgoing planetary

infrared radiation by perhaps twice that amount, at the

earth's surface. It is possible to pro~ote the develop-

ment of much more widespr~ad cloudiness than a typical

contrail by using aircraft to release l~rge numbers of

ice nuclei So that orders of magnitude more ice particles

are created per unit length of flight p~th than are created

in "normal" contrails. Opportunities also exist for clear-

air seeding near the surface in cold climates. Investiga-

tions into suitable ice nuclei, synoptic weather conditions

and seeding schemes are presented. The radiative properties
of cirrus clouds are discussed.