WMOD00402

• Project Name: Sierra Cooperative Pilot Project
• Title: Sierra Cooperative Pilot Project - Final Report for Period November 1984 - September 1986
• Date: 6/1/1987
• Weather Modification - Doc Type: Report

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1.5

The highest priority in the program is to obtain the IMtJ and Ineteoro-
logical data, to various computations and building up data buffers. The
next priority is writing both position and meteorological dat~ on 1tape1
lowest priority is assigned to the ~T display which is every 10 slaconds.

Tape drive failures are handled by a tape recovery routi.ne which re-
initializes the tape drive controller and displays a message on thla CRT
for the appropriate measures to be taken. As a result the operator will
manually restart the tape drive (if a severe failure occurs).. In illl other
cas.es the tape drive will automatically restart.

(b) The Pliqht Proqram:

The subcontract for the SP6 was awarded to North AmericcLn Weather
Consultants (NAWC) because of the familiarity of Richard Benner,. olE their
staff, with the SF 6 detecting equipment DRI rented from Dr. Ih'ian :r.amb,
Washington State University.

Richard Benner arrived at DRI 21 March 1985 and helped udjust and
install the instrument into the aircraft. He took charge of the ground
release of the SP6 gas.

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The initial flight was for 1.5 hours on 25 March 1985, :Ln the area of
Stead Airport. The SF 6 proved easy to de,tect at close range and the instru-
ments were all checked out. A number of aspects of the ordel~ in which the
graphical display is drawn needed to be changed so that the display was
readily visible at all times and the map was not concealed by the drum or
the pen block. These were then reprogrammed. Adjustment on the S:1:'6
instrument for optimum performance proved to require patienc~a and skill,
and Benner I s participation proved essential to the success oj: the program.

The series of SF6 tracing flights which began just befo]~e the end of
the second quarter were completed at the beginning of the third qusrter.
The procedure worked well although a number of minor problenus had to be
solved before the equipment was entirely trouble free.

The graphical outputs from the 22 April 1985 flight are given as
Figures 1.2-1.6. These are direct reproductions of the real.-~ime plotter
output. Figure 1.2 shows the start of the flight at Stead Airport. The
strip charts at the top of the plot show altitude in kilometers with only
the fractional part plotted. When the tI'ace exceeds the limits, a unit of
1 kilometer is added or subtracted to keep the trace on scalIa, and the trace
annotated with the integer value which applies to the next section. Thus at
12:48 in Figure 1.2 the altitude begins a~t about 1.6 kilometlars (Stead Field
is 5060 or 1542 m). The SP6 output records volts from the instrument. It
starts at about 1.3 and is then adjusted to about 0.1 Volts. At 12:50 the
instrument is calibrated with a 25 ppt SE'6 sample and again ist 12: 54 . Some
adjustments were then made. Thus the sensitivity is about 50 ppb/Volt.