Airborne Cloud Seeding for Hail Suppression in North America

Airborne Cloud Seeding for Hail
Suppression in North America
Hans P. Ahlness
hans@weathermod.com
Vice President of Operations
Weather Modification, Inc.
Fargo, North Dakota, USA
www.weathermodification.com
Hail Suppression - Antigranizo
• Cloud seeding, via
aircraft delivery, to
reduce hail damage.
• Two WMI programs.
• There are similarities
and differences.
AGRICULTURE
PROPERTY
Program Locations
WMI conducts two
North American hail
suppression programs.
One, located in western
North Dakota, USA, has
been ongoing in it’s
present form since
1974.
The other is located in
Alberta, Canada, and
has been ongoing since
1996.
Program Locations
• 1- North Dakota
Cloud Modification
Program (NDCMP)
27,000 sq km
2
1
• 2 – Alberta Hail
Suppression
Program (AHSP)
28,800 sq km
Program Similarities
NDCMP
and
AHSP
• Glaciogenic seeding, beneficial
competition hypothesis.
• Exclusively airborne seeding.
• 24 hour operations (day & night).
• Seeding from cloud top and base.
• Operations directed from radar
operations centers.
• Real-time seeding decisions made
by the flight crews.
• Flight and seeding data are
recorded and archived.
• Seeding agents provided by Ice
Crystal Engineering.
Some Program Differences
NDCMP
• Began 1961, current form
since 1974.
• Seeding is intended to
protect both property and
crops.
• Sponsored by local county
government with State costsharing.
• Radars and meteorologists
provided by State of North
Dakota.
• Program directed by State
meteorologists, using WMI
aircraft and pilots.
AHSP
• Current form since 1996.
• Seeding is intended to
protect property only, not
crops.
• Sponsored and funded by
property insurance
companies.
• Radar and meteorologists
provided by WMI.
• Program directed by WMI
meteorologists, with WMI
pilots and aircraft.
Chain of Events – Precipitation
• Natural clouds are
often inefficient: few
SUPERCOOLED
ice particles develop,
WATER BUILDS but become very
HAIL.
large (hail).
• Glaciogenic seeding
speeds ice formation,
resulting in many
small ice particles
that can melt before
reaching the ground.
Mitigation Strategy
Project
Areas
ND Target Areas
Alberta Target Area
Radar Sites
Alberta Radar Site
ND Radar Site
North Dakota Equipment
8 Aircraft (5 Piper Seneca II, 2 Cessna 340A, 1 Piper Cheyenne II)
BIP Flare Rack (all)
Acetone Generator
(cloud base)
Ejectable Flare
Rack (Cheyenne II,
C340A)
Dry Ice
Dispenser
(Cheyenne II
only)
Alberta Equipment
5 Aircraft (3 C90A King Air, 2 Cessna 340A)
C90A King Air – BIP and EJ flares
Cessna 340A –
BIP and EJ
flares, acetone
generators
WMI Cloud Base Aircraft
ND C340A Hybrid Seeder
ND Seneca II AgI Generator
Alberta C340A Base Seeder
Alberta C90A BIP Flare Racks
WMI Cloud Top Aircraft
Alberta C90A King Air
ND Piper
Cheyenne II
THE VIEW FROM THE AIRPLANE DOESN’T
MATCH THE RADAR PICTURE
TITAN Radar View
This is what the Meteorologist Sees
•
•
•
•
Storms overlaid on Map
Intensities shown by colors
Aircraft tracks shown
“Composite View” – shows
highest intensities at any
altitude in storm
• Easy to pick out target
storms
This is what the Pilot Sees
• New cloud growth areas
sometimes obscured by
other clouds
• No map of storms
• Visual cues to find new
growth and updrafts
• Pilots and
Meteorologists must
communicate effectively
to ensure proper seeding
Basic Storm Structure
Multicell Storm Life Cycle
Schematic view of
multicell thunderstorm as
might be seen with radar
(color shading) and
visually (white) cloud
outlines.
Most thunderstorms
are comprised of
many cells, each in a
different stage.
Front Feeding Line – More Complex
Line Formation – Where do We Seed?
Flight Safety Around Storms
• Concerns
– Terrain
– Hail
– Wind shear
– Turbulence
– Lightning
Evaluations
• North Dakota - ~45% decrease in crop loss
– NDSU Economic Evaluation
– Smith et al. JAM, crop-hail statistics
• Alberta – no interest in funding physical
research, mostly focused on the bottom line.
Alberta Physical Evaluation using
Weather Radar
• TITAN radar parameters such as Vertical Liquid
Water (VIL), Vertical Integrated Hail Mass, and
Kinetic Energy Flux have shown reduced storm
intensity after seeding.
• See next slide for an example
Storm Vertical Integrated Liquid (VIL)
Before Seeding
After Seeding
This storm on 12
August 2012 showed
an estimated 40%
reduction in VIL after
seeding, but still
caused >$500 Million
CD in property damage
in Calgary.
Ask Me Anything
Hans Ahlness
Vice President – Operations
Weather Modification, Inc.
Hans@weathermod.com
+1 701-235-5500