WMOD00079

• Contract/Permit #: #98-1
• Applicant: Western Kansas Groundwater
• Project Name: Kansas Weather Modification
• Date: 1/1/1998
• Weather Modification - Doc Type: Report

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Using a computer-interfaced radar system allows us to quickly analyze clouds for hail potential.
The height of the 45 dBZ intensity contour within a cloud is evaluated against a "hail threshold"
computed daily based upon the height of the freezing level. The height of the 45 dBZ intensity level
within clouds is used as a test for determining the crop-damaging hail potential in storms and its
destructive potential relative to other storms. It provides quantifiable information crucial to making
operational decisions regarding aircraft guidance during operations. Radar echo output is displayed
in colored contours viewed on a computer monitor. This basic technique to determine whether or not
there is crop-damaging hail in clouds has been used continuously on the WKWMP, in one form or
another, since 1985. It's easy to calculate, even without a computer, provides sufficient accuracy
and is reliable. Although one person can run the system, it works best if during operations the
meteorologist can focus on providing aircraft guidance while his assistant operates the computer,
collects weather data, updates weather information for the meteorologist's examination and moves
radar data to the Internet both for pubic viewing and for the Colby radar site. team to monitor. In the
PPI mode the background display automatically shows all regional boundaries, counties, neighboring
counties, state lines, VOR navigational aids and the locations of regional towns.

C. AIRCRAFT SEEDING OPERATIONS AND MAINTENANCE

The cloud base seeding and one cloud-top seeding aircraft type used in 1998 were:

(1) 8-single-engine Piper Aircraft Comanches, PA24-250

(2) I-twin engine Piper Navajo Chieftain, P A31-325

All cloud base planes were equipped with Carley-type liquid fuel generators, one mounted to
each wing tip. Each generator carries 6 gallons ofliquid seeding solution and bums silver iodide at a
rate of two grams per minute of operation (two gallons ofliquid solution burned per hour). Each full
generator carries a total of 3 60 grams silver iodide and can bum continuously for 3 hours. In 1998
cloud base planes were stationed at Lakin, Johnson, Syracuse, St. Francis and Tribune. Two planes
were based both in Scot! City and in Goodland. The cloud top plane was based in Dodge City.

All aircraft are equipped with Global Positioning System (GPS) technology. Using GPS allows
pilots and meteorologists to precisely reference distance and direction from each radar site, giving us
a high degree of precision with respect to storm position. The GPS units have served us extremely well
since being put into operation in 1993. A second GPS unit is also maintained on board used to record
seeding events and flight track information.. .

Also incorporated into our operational radar systems are aircraft interrogator/transponder
(IFF) flight tracking systems. These systems can simultaneously track six discrete transponder codes
in Lakin, but just three codes in Colby. The cloud base aircraft can use any of 8 codes assigned to us
by the Federal Aviation Administration in an agreement with them in 1997. Cloud top flights are given
a different code with each flight since it doesn't operate under Visual Flight Rule regulations.

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