WMOD00306

• Project Name: Sierra Cooperative Pilot Project
• Title: Sierra Cooperative Pilot Project - Operations Plan - 1986-1987
• Date: 10/1/1986
• Weather Modification - Doc Type: Report

It is the responsibility of the forecaster or Site Director during off hours
to input the available wind information into the GUIDE model on the Perkin-
Elmer to calculate which ground generators will directionally target the pre-
scribed area and/or calculate a VOR/DME Q point and seeder aircraft heading to
begin aircraft seeding operations. Because the randomization for ground seed-
ing will be known to the forecasters on all no-seed draws, aircraft seeding
can be conducted. Thus, 6 hours will be available for aircraft seeding before
a new ground seed-no-seed decision is made. The cloud physics aircraft winds,
if available for either ground or aircraft seeding, cloud base and top temper-
atures, levels and type of icing and temperature and amount of liquid water as
observed on aircraft descent down the MOCA will be documented as shown on the
form in fig. 2-9. For aerial seeding, if the Q point location places the
seeder out of cloud, seeding can be conducted if it is felt the AgI plume will
be carried into cloud within a short period of time. This will allow visual
link up of the two aircraft if both are available and improve the chances for
initial detection of the AgI plume.

D. RANDOMIZATION
Because of two separate seeding experiments this field season randomization
will be handled as follows. For ground seeding, a set of envelopes will be
kept in the forecast office. Each will contain a IIseedll, IIno-seedll selection
based on a 2 to 1 ratio. The forecaster on duty will not open the envelope
until he has decided the ground seeding criteria have been met or will be
within 2 hours. Once the envelope is opened a randomized ground seed experi-
ment is called and the experimental unit will begin 2 hours later. If the
draw is a IIno-seedll, documentation of ground generator on and off times should
be noted even though no seeding actually takes place. Eleven hours later, if
a IIseedll and 6 hours for a IIno-seedll,if conditions persist and are expected to

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