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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. Basic SFMR Theory. Data Handling. Raw counts converted to Tb’s using AOC-derived calibration Linear Least-Squares fit outlier filter – same as P-3s
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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
Data Handling • Raw counts converted to Tb’s 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
Typical Flight Track Triangles are dropsonde splash points
Peak 10 Sec Wind Average in 30 Sec Window Potential Real-Time Product
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 • Don’t want to tighten up on roll threshold because of aircraft behavior in turbulence
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