WMOD00568

• Project Name: Snowater
• Title: Snow Water Augmentation for the Eastern Slopes of the Rockies - Stage I: Technology Adaptation
• Date: 6/1/1986
• Weather Modification - Doc Type: Report

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relatively thin layers within one kilometer of barrier crests.

2.5.2.2 Research Aircraft Measurements

In this activity an instrumented aircraft would be used to determine
precipitation formation processes in seeded and un seeded orographic
cloud systems. By penetrating these systems their microphysical
characteristics and precipitation conversion efficiency would be
documented.

Of fundamental importance to this activity would be the measurement of
ice crystal concentrations, ice crystal types and growth rate, cloud
liquid water contents, vertical velocities, and aircraft position as
functions of time. All necessary steps to ensure flight safety would
be taken.

2.5.2.3 Physical Evaluation Studies

In order to define the physics of precipitation processes in
orographic clouds, data from Year Two would be analyzed on a case
study basis. Seeding signatures would be sought in the evaluation of
cloud structure and precipitation.

2.5.2.4 Transport and Diffusion Studies

Investigations into the rate of diffusion of airborne silver iodide
releases have revealed limited mixing rates that are terrain dependent
in stable free atmospheres. Seeding aircraft need to be positioned
sufficiently upwind of the target barrier for adequate diffusion of
seeding material. Transport and diffusion work is needed for each
release site to determine the extent to which mechanical mixing
enhances diffusion in mountainous terrain.

This program would continue the initial studies started in Year One
and would document the region of the atmosphere that could be affected
by ground-released silver iodide and optimize aircraft delivery of
seeding material. The plume tracing program would use airborne tracer
materiai and detectors to determine the transport and diffusion of
seeding material over the barrier. Airborne sampling would be
supplemented by surface measurements where access permits.

In adeition, the Dopplerized radar would be valuable in determining
the wind field to help in targetting seeding materials. Radar
measurements would also be used to document the existence of low-level
barrier wind jets that may have significant implications for the
targetting of ground-released seeding materials.

2.5.3 YEAR THREE - FULL SYSTEM TEST

A Full System Test would occur during Year Three. Ground-based and
airborne cloud seeding would be carried out on opportune targets as
identified by the SNOWATER Seeding Opportunity Recognition System.
Additionally surface precipitation measuring sites would be activated.

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