WMOD00413

• Title: Validation of Precipitation Management by Seeding Winter Orographic Clouds in the Colorado River Basin
• Date: 9/1/1993
• Weather Modification - Doc Type: Report

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GLOSSARY

a.g.l.: above ground level.

AgI: silver iodide.

AMS: American Meteorological Society.

BLM: Bureau of Land Management.

CE: categorical exclusion.

CEQ: Council on Environmental Quality.

COR: linear correlation coefficient.

CRBPP: Colorado River Basin Pilot Project.

CREST: Colorado River Enhanced Snowpack Test.

Chaff (radar): small glass fibers coated with aluminum that are excellent reflectors of radar
energy. Chaff can be dispersed in the atmosphere and tracked by radar to provide information
on transport and dispersion and air motions.

Condensation (water): the physical conversion of water vapor into liquid water that takes place
at relative humidities near 100 pct for typical atmospheric conditions.

Convection: vertical motions set off by thermodynamic instabiltiy ill the atmosphere;
convective clouds (e.g., cumulus) are a visible manifestation of convection.

Convective Instability: a state of an unsaturated column or layer of air that permits it to
become unstable if it becomes saturated through lifting and associated cooling, resulting in
liquid cloud formation; that is, the air has the potential to become unstable, leading to
convection and vertical motion, if it is lifted sufficiently, as when forced over a mountain
barrier.

Dispersion: in this report, the horizontal and vertical spreading or mixing of a substance like
silver iodide or tracer gas due to turbulent motions in the atmosphere; the turbulence can be
mechanically induced, when set off by interactions between the airflow and rugged terrain, or
convectively induced, or both.

Doppler effect: in this report, the change in frequency of reflected mircowave radar energy due
to relative motion between the target and the radar; this effect allows for the measurement of
horizontal arid vertical winds by Doppler radar.

EA: environmental assessment.

EIS: environmental impact statement.

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