Storm Chasing and our Basic Understanding of Thunderstorms and Tornadoes: The Recent Past

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Storm Chasing and our Basic Understanding of
Thunderstorms and Tornadoes The Recent Past

• Dr. Louis J. Wicker
• National Severe Storms Laboratory
• Norman Oklahoma

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NSSL, Storm Chasing, and Science?

• Storm chasing as a scientific activity has
  existed since the early 1970s.
• During the 1970s and early 1980s, it was used
  to provide ground truth for Doppler radar
  observations.
• Significant collaboration between NSSL and OU
  researchers.
• After the early 1980s, chasing began to evolve
  from visual data collection toward
  meteorological data acquistion.

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NSSL, Storm Chasing, and the Public?

• Storm chasing documented a wide variety of
  supercell and tornado structures.
• Chaser observations connected what the Doppler
  radar saw with what was happening below the cloud
  base.
• The correlation between radar rotation and storm
  rotation led to the deployment of the new U.S.
  Doppler radar network in the late 1980s.
• Subsequently tornado warning lead times for the
  public have increased from 5 to nearly 15
  minutes.

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Mobile Instrument Time Line
1980
1990
2000
2010
Mobile Mesonets
Turtles
Surface
Stereo Video Turtles
TOTO
2nd Gen Turtles
1st Doppler on Wheels
FM-CW Radar
2nd/3rd DOWs
Radar
Mobile Phased Array radar
W-band radar
SMART radars
1st Mobile Ballooning Electric Field
Mobile Balloon and Command Vehicles
Unmanned Aerial Vehicles
Balloons
Mobile Digital Network Satellite
Live Field Data Back Via Satellite
Radio Transmission of Data to CMD Vehicle
Technology
VORTEX (1994-1995)
STEPS (2000)
IHOP (2002)
VORTEX-II? (2007-2008)
FIELD PROGRAMS
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Totable Tornado Laboratory(TOTO)

• Developed by Howard Bluestein (OU) and Al Bedard
  (WPL) in 1980.
• Deployed from 1981-1985.
• Collected data under several tornadic storms.
• Hard to get into the direct path of the tornado.
• Spearheaded the effort to obtain in situ data
  from supercells.

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Turtles

• Simpler instrument than TOTO P T measured.
• Deploy 6-10 turtles along the road where tornado
  may cross.
• Measurents are now obtained along a line, not a
  point.
• Better chance for a direct hit.

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Mobile Mesonets

• Designed for VORTEX field program.
• Continuous wind, pressure, temperature and
  humidity every second.
• GPS was
• needed!
• Fleet can map
• the weather
• around
• the tornado.

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Latest Generation Turtles!

• Ultra-high frequency measurements of pressure and
  wind.
• Now includes high-speed video!
• Requires great
• skill and luck
• to place in a
• tornado..but
• it can be done!

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Mobile Doppler Radars

• 1987 FM-CW Doppler (Bluestein)
• First truly mobile Doppler radar used for severe
  storm research
• Broad beam, low resolution.
• Sampled maximum winds in several tornadoes.
• Max wind speeds 100 ms-1

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Mobile Doppler Radars

• 1996 Doppler on Wheels
• (DOW)
• High resolution due
• to large dish and 3 cm l.
• First deployed in
• VORTEX program in 1995.
• Observed several tornadoes in 1st year, including
  the Dimmitt tornado.

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Mobile Doppler Radars
Harper KS (2004)

• What have we learned?
• Tornadoes have holes!
• Internal structure can be complicated.
• Maximum wind speeds approach 150 m s-1.

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More Mobile Doppler Radars
OU-UMass W-band
SMART Radar
Hurricane Isabel Sept 2003
Eye
N. Carolina coast
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Mobile Ballooning

• Used to obtain upper air soundings from in and
  around the storm.
• Sample the inflow environment
• Sample the inside of the storm
• Mobile implementation of the CLASS sounding
  system in 1990
• (Dave Rust NCAR)

Soundings with mobile lab and high- wind balloon
launch device
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Mobile BallooningStorm Environment

• Used to understand what environments produce
  tornadoes.
• Found out that the atmosphere varies greatly
  around the storms.
• Good forecasts of the daily storm and tornado
  threat requires more detailed and localized data
• Oklahoma Mesonet
• Wind Profilers

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Mobile BallooningElectric Field Balloon
Instrument Train
photo by Dan Petersen
Into the updraft we must go!
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The Future

• Mobile digital networks of turtles, radars,
  mesonets, ballooning systems, UAVs, mobile phased
  array radars, and other unique instruments.
• Complete integration of data into command
  vehicle.
• Transmission of real-time data to the local or
  regional forecast office.
• Able to deploy for research work and potentially
  operational situations where warranted (e.g.,
  landfalling hurricanes).

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The Future

• Benefits
• Better understanding of severe storm and tornado
  processes
• improved forecasts and warnings.
• More detailed information to public during
  critical situations.
• Weather modification?

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Special Thanks To

• Dr. David Rust, NSSL
• Dr. Howard Bluestein, OU
• Dr. Josh Wurman, CSWR
• Tim Samaras, Applied Research Associates
• All those students
• And many others