WMOD00294 ‎(2)‎

• Title: Thailand Applied Atmospheric Research Program - Final Report - Volume I
• Prepared For: US Agency for International Development
• Date: 3/1/1994
• Country: Thailand
• Weather Modification - Doc Type: Report

A temperature controlled and power regulated computer room was developed within the
RRRDI office complex. Most of the scientific analyses for the AARRP are performed with
USAIn provided computers located in this room.

The RTG provided all seeding chemicals and delivery systems. The cold cloud flare rack
system, purchased from AI (Atmospherics, Inc.), was a standard flare rack for ejecting 20-
millimeter cloud seeding flares. Figure 3.1 shows the flare rack ready for mounting on the
high-altitude seeding aircraft. The AgI (silver iodide) pyrotechnic flares purchased for
Thailand were the AI model EJ-20-E-20 type FA6, which have dimensions of20 millimeters
diameter by 120 millimeters length. This flare is a chlorinated formulation, strongly
hydrophilic, with a fast nucleation rate. These dropable flares contain 20 grams of AgI and
bum at a rate of 0.5 gram per second. Although the RTG uses various hygroscopic chemicals
for their warm cloud seeding operations, only the chemical CaCl2 (calcium chloride), which
was factory bagged, was used on AARRP Phase 1 warm cloud studies.

In the past, RRRDI had no aircraft of their own for conducting cloud seeding operations, and
had to obtain them from the AAS. However, the recent reorganization that placed RRRDI
and AAS both under the BRRAA, should make the coordination of the warm cloud seeding
aircraft, helicopter support, and air crews needed for Phase 2 of the AARRP easier. Figure
3.2 shows a CASA aircraft from the AAS that has and will be used for the AARRP's
randomized warm cloud seeding operations.

Because the AAS does not have a high-altitude pressurized aircraft, the RTG entered into a
3-year lease with Thai Flying Service for an Aerocommander 690B twin-engine turboprop
aircraft (shown on figure 3.3). This aircraft was fitted with an RTG-procured dropable flare
system for the on-top seeding of cold convective clouds, and a cloud physics data acquisition
system provided by USAID. The lease of this aircraft has been extended by the RTG through
1995.

In 1990, the RTG constructed a radar research site within the AARRP study area near
Omkoi, about 120 kilometers south-southwest of Chiang Mai. The USAID-provided Doppler
weather radar system was installed at this site during the summer of 1991. This permanent
site is also used as the base of operations for servicing the automatic recording rain gauges.
In 1993, the use of this site was expanded to include an instrumented TMD weather
observation area, an upper air observation capability, and a NASA (National Aeronautics and
Space Administration) GMS ingest and display system. Figure 3.4 shows a view of the radar
site from the air. Figures 3.5 and 3.6 show photos of the radar antenna tower and control
building, and radar system control room, respectively. Figure 3.7 shows the standard surface
meteorological observation installation, and figure 3.8 shows the GMS antenna installation
at the radar site.

Figures 3.9 and 3.10 show the AAS helicopter used for the installation and servicing of the
AARRP's recording rain gauge network at one of the fenced rain gauge sites, and the
technician checking the gauge calibration. RRRDI personnel built and installed fences for
about 50 sites; NASA provided the recording rain gauges under an agreement where RRRDI
provides copies of the recorded rainfall data to NASA for their TRMM (Tropical Rainfall
Measuring Mission). Figure 3.11 shows AARRP personnel downloading recorded rainfall data
using a data translator and a personal computer.

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