Noise Assessment

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Noise Assessment Prediction System At Aberdeen
Test Center
by Charles Clough
24 April 2001
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PROPAGATION MEDIUM
LOWER ATMOSPHERIC BOUNDARY LAYER
Receptor Response
Blast Energy
S (x,y,z,t) f (? Tv , WS? )
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BOUNDARY-LAYER METEOROLOGY

• Virtual Temperature Gradient

Wind Vector Gradient
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NOISE ASSESSMENT PREDICTION SYSTEM

• Ray-Trace Model
• Developed by University of Dayton Research
  Institute (Dr. James Luers Project Manager
• One-Dimensional characterization of the
  atmosphere (vertical gradients only)
• Two-Dimensional characterization of the terrain
  (includes elevation, land and water impedance's)
• 80-85 effective in specifying sectors of
  acoustic focusing over the past 10 years of
  operation

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IMPROVEMENT PROGRAM

• Added More Blast Sites
• Added Ensemble Computation Capability

1996

• Added More Blast Sites
• Added Prediction Uncertainty Capability

1999
2000 ?

• Development of Pre-Ensemble Data Algorithm
• Sensitivity Research to Link with 4DWX Model
  Output

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NEED

• PREDICTION OF TEMPERATURE AND WIND GRADIENTS
  THROUGHOUT THE APG AREA 12-24 HOURS AHEAD

ANSWER
"4DWX" PROJECT

• Nonprofit consortium of 61 universities with
  doctoral programs in
• the atmospheric and oceanic sciences.
• Supported by the National Science Foundation

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115 dBP Forescast for 28Mar00 1500L (Morning
Estimate 1045 hrs) as of 28Mar00 w/125 dBP in
red
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115 dBP Forescast for 28Mar00 1500L as of 28Mar00
w/125 dBP in red
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4DWX Enhancements at ATC

• Hourly forecast mode (initialization at 0700hrs
  and 1900hrs daily)
• To 1900hrs (available at 0700hrs)
• To 1900hrs next day (available at 1530)
• Post-test analytical mode (FDDA)
• Ingestion of all local measurements
• Mathematical/Physical integration with 3-D fields
  for each hour

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4DWX Enhancements at ATC (contd)

• Real-Time FDDA
• FDDA up to t-1 hour
• Forecast from FDDA out to 6 hours
• Test can adapt to weather on-the-fly

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4DWX Enhancements at ATC (contd)
RT-FDDA ingests data points irregularly located
in space and time into the 3-D field of variables
to produce a dynamically-balanced data-set.
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