First Results from a High Altitude SFMRFirst Results from a High Altitude SFMR

Alan S. Goldstein, NOAA/Aircraft Operations Center

Dr Eric Uhlhorn, NOAA/Hurricane Research Division

Alan S. Goldstein, NOAA/Aircraft Operations Center

Dr Eric Uhlhorn, NOAA/Hurricane Research Division

Basic SFMR Theory

Brightness Temperatures (theoretical)

100

120

140

160

180

200

220

4 5 6 7 8GHz

Ke

lvin 0 WS 0 RR

30 WS 0 RR

0 WS 30 RR

30 WS 30 RR

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

080911n Flight Track - Hurr Ike

21

23

25

27

29

31

-98 -96 -94 -92 -90 -88 -86 -84 -82

Triangles are dropsonde splash points

30 sec avg vs Dropsonde

080911n - Hurr Ike

0

5

10

15

20

25

30

35

40

17

:32

:00

18

:02

:00

18

:32

:00

19

:02

:00

19

:32

:00

20

:02

:00

20

:32

:00

21

:02

:00

21

:32

:00

22

:02

:00

22

:32

:00

23

:02

:00

23

:32

:00

0:0

2:0

0

0:3

2:0

4

SFWS (m/s)

SFRR (mm/hr)

Sonde WS (m/s)

Error Scatter Plot – 5 Flights, 128 points

2.5 m/s RMS Error0

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10

15

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30

35

0 5 10 15 20 25 30 35

Sonde m/s

SF

MR

m/s

Potential Real-Time ProductPeak 10 Sec Wind Average in 30 Sec Window

25

27

29

31

-94 -92 -90 -88 -86 -84

>64 kts

>50 kts

>34 kts

<34 kts

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