WSPC03885

• File Number: 8200.700
• Description: Colorado River Basin General Publications - Augmentation-Weather Modification
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/1/1993
• Author: DOI-BOR
• Title: Validation of Precipitation Management by Seeding Winter Orographic Clouds in the Colorado River Basin - Draft
• Water Supply Pro - Doc Type: Report/Study

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Figure 1. - Conceptual model of orographic cloud w;th SLW zone and AgI seeding plume.

temperatures slightly colder than 0 oC. Previous measurements suggest the crosswind spacing
between AgI generators or propane dispensers should be no more than 2 to 3 km to affect most
of the crosswind extent of the SLW zone.

3.2 Seeding Hypothesis

A detailed hypothesis concerning the effects of seeding v."inter orographic clouds will be stated
prior to the onset of the statistical experiment (sec. 5). The hypothesis will be based on the
results of the direct detection experiments (sec. 4) and on numerical modeling. The hypothesis
likely y..-ill. be based on what is generally referred to as the static seeding mode as opposed. to
dynamic seeding, which is intended to release abundant latent heat. However, the modeling
results of Orville et aI. (1987) suggested that seeding layer clouds may cause embedded
convection under some atmospheric conditions, leading to enhanced liquid water production_
Hence. d.ynamic effects sometimes may be produced by presumed static seeding, and this
possibility will be investigated with the direct detection experiments. If significant dynamic
effects do occur, they are expected to increase the seedability of the cloud systems because of the
additional SLW availability.

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