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Comparison of Factors Relating to Aircraft vs Ground-based
Seeding Methods
Aircraft Seeding
| Pros |
Cons |
| Can seed
upwind of and
over
wilderness areas, where ground generators are not allowed |
Aircraft flight operations are substantially
more expensive than seeding by ground generators |
| Can seed high-elevation SLW regions, such as
those produced by gravity waves or convective clouds (if such regions can be
identified in advance so as to be reached by aircraft) |
Difficulty in seeding most common SLW zone
within 3000 feet of the surface, because of FAA altitude restrictions
and
flight safety concerns. |
| If SLW region is too warm for effective ground
seeding (AgI is only effective at -5°C or colder), it might be possible to
reach the sufficiently cold altitudes of this region with aircraft seeding |
Dangers posed by exposure to icing conditions,
especially in darkness |
| |
Difficulty in filling SLW cloud
volume adequately with seeding material so as to produce seeding effect on
the ground (more research needed). |
Ground-based Seeding
| Pros |
Cons |
| Much less expensive compared to operating aircraft |
Cannot locate generators within wilderness areas |
| If no trapping by temperature inversions, generators can
routinely seed the nominal SLW zone within 3000 feet of surface |
Fixed generator locations require siting studies for
effective seeding of target (includes T&D analysis) |
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High altitude sites, more than midway from the valley floor
to the mountain crest, result in routine transport of AgI and/or
seeded crystals over the crest. This will likely add cost however,
especially if access issues necessitate remotely-controlled generators. |
If there is significant trapping of seeding
materials from valley-based generators, they will not achieve routine
seeding of the target area. |
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SLW region may be too warm for effective seeding (AgI is
only effective at -6°C or colder), particularly in warmer climates. It
may be possible to seed instead using liquid propane (effective as warm as
-2°C). |
Return to Ground-Based vs Aircraft Seeding Page
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