WMOD00307

• Title: A Proposal for Cooperative Weather Research Between the Santa Barbara County Water Agency and the US Department of Interior Bureau of Reclaimation in the Context of the Weather Damage Modification Program through the State of CA 2002-2003 Winter Season
• Date: 10/17/2002
• State: CA
• Weather Modification - Doc Type: Report

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A significant amount of aircraft plume tracing near mountains has been done on earlier projects.
Super (1974) discussed VFR plume tracing using an ice nucleus counter over the Bridger Range
of Montana. The findings of successful transport and dispersion of the seeding agent provided
physical support to the strong statistical suggestions that seeding resulted in seasonal snowfall
increases of 15 percent or more over the intended target area (Super and Heimbach 1983). Later
IMe sampling with an aircraft instrumented to measure cloud microphysics showed AgI over the
target, and also associated seeded ice crystal plumes when SL W clouds were cold enough for the
AgI to be effective (Super and Heimbach 1988).

When synoptic conditions are deemed appropriate by the project forecaster, a serial rawinsonde
release will be made upwind of the target area, and the sounding data used to initialize the WMI
Targeting Model. This targeting model has its roots in the Guide Model developed by Rauber et
at. (1988), but has been updated and modified to run in real-time on a Pentium-class Pc. The
output from the targeting model will be used to predict the transport and dispersion of the
seeding agent, and the aircraft sampling.flight path will be planned accordingly. Examples of the
output from the model from a simulation of ground based seeding in British Columbia are
provided in Figure 11 (plumes from ground-based sites) and Figure 12 (sample terrain).

Weather Damage Modification Program 27