First Results from a High Altitude SFMR

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First Results from a High Altitude SFMR
Alan S. Goldstein, NOAA/Aircraft Operations
Center Dr Eric Uhlhorn, NOAA/Hurricane Research
Division
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Basic SFMR Theory
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Data Handling

• Raw counts converted to Tbs using AOC-derived
  calibration
• Linear Least-Squares fit outlier filter same
  as P-3s
• Standard retrieval algorithm and emissivity
  curve
• SSTs from MW-IR data
• Data comparison Wind Speeds and Rain Rates are
  30 sec
• averages
• Winds in HDOB example are highest 10 sec avg
  over 30 sec
• span
• Dropsonde reference winds are .83 L150 from
  TempDrop
• reports

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Typical Flight Track
Triangles are dropsonde splash points
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30 sec avg vs Dropsonde
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Error Scatter Plot 5 Flights, 128 points
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Potential Real-Time Product
Peak 10 Sec Wind Average in 30 Sec Window
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Differences from Low Altitude and TurboProp Ops

• Bigger footprint (5x) means some data smoothing
• Faster airspeed may produce noisier data (may
  not be noticed at
• 10 second average may be reduced by
  footprint data
• smoothing)
• Roll angle issues
• Sometimes G-IV makes gentle turns that do not
  exceed the roll limit threshold emissivity
  equation should compensate
• Ocean patch being sampled can be further
  off-track
• Dont want to tighten up on roll threshold
  because of aircraft behavior in turbulence

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Some Remaining Issues

• Intervening Precipitation
• Performance seems reasonable, but more data
  needed
• Model makes assumption that all precip is below
  4 km, may not be accurate for tropical convection
• May need to wait for Tail Doppler Radar (TDR) to
  characterize vertical precip profile
• Use aircraft pitch angle in retrieval algorithm
• RF interference from TDR (probably a non-issue)
• Transition to Operations
• Decision are we ready to share?
• Integrate AOC algorithm into G-IV data system
  3/09
• How to get data to the ground - HDOB? But some
  fields (e.g. humidity) will need to be left blank