WMOD00301 ‎(2)‎

• Title: Conceptual Plan to Develop Water Augmentation by Weather Modification in the Colorado River
• Date: 5/14/1979
• Weather Modification - Doc Type: Report

ORA F T

conditions. To recognize a seedable opportunity routinely, the
conditions must'be readily identifiable by standard observation
techniques. Past experiments have used indices (500-mb temprature
and cloud top temperature) that were easily identifiable but were
not good indicators of seeding opportunity or potential. Vardiman
and Moore have reanalyzed the results of seven winter seeding
programs in an effort to identify and generalize the key parameters
of these conditions into seedability criteria that are applicable to
a variety of meteorological and topographic conditions. They were
able to stratify the conditions into four physical categories.
These categories indicate the availability of water, nuclei, mixing,
and time 30/.

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Each of these physical categories identified has a number of parameters
which were associated with or affected seeding results. In general,
cloud seeding can be expected to increase the amount of precipitation
produced when: (1) there is an abundance of moisture in the form of
supercooled liquid water, (2) there is a deficiency of natural ice
nuclei, (3) the air is unstable, (4) the time required for growth and

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