WMOD00176

• Project Name: Annual Report
• Title: Seeding Operations & Atmospheric Research, 2005 Annual Report
• Prepared By: Duncan Axisia
• Date: 12/31/2005
• Weather Modification - Doc Type: Report

These analyses confirm that seeding operations
in the Southern Ogallala target are having a
positive impact on the area rainfall to some
extent. Clouds that traverse the Southern
Ogallala target area appear to be receptive to
glaciogenic seeding. Furthermore, the paper by
Woodley et. al. (2005) and subsequent seeding
trials in April and May of 2005 suggest that
hygroscopic seeding is suitable for the SOAR
target area. On numerous occasions during the
seeding trials, the SOAR research aircraft
located the seeded plume and detected
microphysical seeding signatures after detecting
the SF6 gas that was released by the seeding
aircraft at cloud base. These results give the
SOAR program confidence in the conduct of its
operations, additional experience in the area of
weather modification research and an
improvement in its seeding methods to maximize
the potential of advertent weather modification.

Recommendations

In 2005, SOAR has objectively conducted its
program in a manner as prescribed by
recommendations suggested in the 2004 report.
Some of these recommendations have been fully
implemented, but others need to be further
stressed.

1) The 2002 Woodley and Rosenfeld analysis
(in 2003 SOAR Annual Report) shows that
the seeding effect is very strong after 75 to
450 minutes after the time of initial seeding.
There is no question that seeding treatment
early in the life cycle appears to show the
greatest seeding effect. With clouds that
traverse the SOAR target area most often
moving west to east, it is recommended that
SOAR explore the potential of expanding its
program further west into New Mexico.

2) It has been shown that the climatology of the
SOAR target area is suitable for hygroscopic
seeding. The conduct of the "practice"
deliberate hygroscopic seeding test case
during SPECTRA and its analysis has
produced what appears to be a strong
microphysical seeding signature. If seeding
did indeed change the microphysical
structure of the seeded cloud as
documented, it appears to have done so
primarily through the effect of the giant salt
nuclei and secondarily through a weak
competition effect, possibly due to salt
particles smaller than the desired giant salt
nuclei of 3 to 5 microns. In view of these
strong results documented in Woodley et. al
(2005), it is recommended that SOAR
continue to investigate the potential of
hygroscopic seeding using milled salt.

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3) Timing of the seeding intervention remains a
very important component of day-to-day
clouds seeding operations. It is
recommended that a performance-based
analysis of daily cloud seeding operations be
implemented on the basis of timely
intervention of the seedable cloud. This
should ensure that the Project Meteorologist
is constantly aware of the importance of his
responsibility to vector aircraft to the
seed able cloud in a more efficient manner.

4) Due to the increased workload in the area of
atmospheric research, it is recommended
that SOAR recruit a second full time
meteorologist. Temporary contract
meteorologists need to be trained every
spring, which further increases the workload.
In addition, SOAR should provide the
opportunity to student interns to join the
SOAR crew in the summer. Interns can gain
a lot of experience, which they can in turn
use in the enrichment of their academic
program.

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