Weather Modification and North Dakota

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Weather Modification and North Dakota

• 157th Meeting of the
• Western States Water Council
• Medora, ND
• July 10, 2008

Darin Langerud, ARB/SWC
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Outline

• History
• Research
• Operations
• Future prospects

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ND Weather Mod. History

• Earliest seeding began in 1951
• Ground-based generators
• Aircraft seeding in 1960
• NDARB established in 1975
• Pilot-Intern training program begins

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(No Transcript)
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North Dakota Pilot Project

• Operated from 1969-72 in McKenzie County
• Randomized seeding program
• 75 seed days, 25 no-seed
• Days determined prior to each season
• Seeding conducted by aircraft using silver iodide
  at cloud base

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NDPP Target Area
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NDPP Results - Rainfall

• Increase in frequency of rain events by a factor
  of 2.1 (0.04)
• Increase in the average rainfall per event by
  factor of 1.7 (0.02)
• Increase in total rainfall in the seeded area
  (0.07)
• Potential of 1 inch additional rainfall during
  growing season

Dennis et al., JAM 1975
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NDPP Results - Hail

• Less hail per unit rain volume on seed days
• Case studies of 34 storms indicated that damaging
  hail was usually suppressed when their updrafts
  were seeded continuously

Miller et al., JAM 1975
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Research

• ARB participated in federal research programs in
  NOAA and BuRec
• NOAAs AMP program (1980-1994)
• BuRecs WDMP program (2002-2005)
• Five field experiments in ND during the last 22
  years
• 1987, 1989, 1993, 2006, 2008
• Numerous partners including Federal agencies,
  Universities, and private business

NOAA WP-3D Orion Hurricane Hunter
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POLCAST
Cessna 340
PCASP
1) Drizzle 2) Rain 3) Dry Snow 4) Wet Snow 5)
Vertical Ice 6) Dry Graupel 7) Wet Graupel 8)
Small Hail 9) Large Hail 10) Sm. Hail Rain 11)
Lg. Hail Rain
FSSP
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NDCMP

• Participation is a county decision
• Funding is 2/3 local, 1/3 state
• Ops from June 1-August 31
• Seeding agents Silver Iodide Dry Ice
• Suspension criteria strictly enforced

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Seeding Equipment
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2007 Flights
District II 486 hours
District 1 84 hours
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NDCMP Evaluations

• Crop-hail damage reduced by 45 (Smith et al.,
  1997)
• Results based on a target/control analysis of
  crop insurance data
• Indicated rainfall increases of 5 to 10
• Multiple studies, however, statistical
  significance not strong
• Wheat yields increased by 5.9 (Smith et al.,
  1992)
• Target/control analysis
• Benefit/Cost ratio of 401 (Sell Leistritz,
  1998)

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Future RD

• Pursuing establishment of a new Federal research
  program
• S.1807 (Hutchison-TX) H.R.3445 (Udall-CO)
• Would fund competitive, peer-reviewed proposals
  over a 10 year period
• 10 Million per year, 100 M total

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S.1807 H.R.3445

• Supported by WSWC (Pos.264)
• North American Interstate Weather Modification
  Council (11 western states)
• WMA, Family Farm Alliance, and many state, county
  and municipal organizations
• National Research Council report (2003) called
  for renewed research
• International journal, Nature, called for renewed
  effort (2008)

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N.A. Cloud Seeding Programs
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Thank You