1. Lidar Remote Sensing for Environmental Monitoring IX
Airborne Doppler wind lidar: typhoon research and long flight-leg data sets for data impact studies related to a future space-based Doppler wind lidar
George D. Emmitt, Simpson Weather Associates, Inc. (United States); Ralph Foster, Univ. of Washington (United States); Daniel Eleuterio, Naval Research Lab. (United States)
Lidar Remote Sensing for Environmental Monitoring IX
New Caledonia
18 November, 2008

2. Overview
An airborne Doppler wind lidar (1.6 micron coherent) was flown on a Navy P3 in ONR/NSF typhoon research missions during August/October 2008.
In addition to full vector wind profiles in clear and partly cloudy conditions, a primary research target unique to the Doppler lidar will be the Organized Large Eddies (OLE) that are theorized to have significant impacts on air sea fluxes controlling the evolution of tropical cyclones.
Measurements of the vertical velocity of the water surface allows wave spectra to be computed.
Efforts are underway to process and subset the thousands of lidar wind profiles taken to simulate the coverage expected from a future space-based DWLs such as GWOS and NWOS.

3. Outline Overview of the P3DWL activity in TPARC/TCS08
Wind profiles to augment dropsondes
Prospecting for OLEs as major air/sea interaction factor in developing TCs
MBL aerosol structures and wave spectra
Example of P3DWL data from Typhoon Nuri flights
Examples of DWL data for OLEs
Examples of DWL data for extracting wave data
T-PARC: THORPEX Pacific Asian Regional Campaign; TCS-08: Tropical Cyclone Study 2008

4. P3DWL for TPARC/TCS-08 1.6 um coherent WTX (ARL/LMCT)
10 cm bi-axis scanner (NASA)
P3 and other parts (NRL)
Analyses software (SWA/CIRPAS)

5. The instrument 1.6µm coherent detection 1 mJ 2000 Hz
10 cm two axis scanner, side mounted
GUI with realtime instrument control and data display
Range: 3 – 20 km depending upon aerosols
Weight: <200lb Power: 300 watts

6. The MLX-16 coherent Doppler lidar built by LMCT for the US Army (ARL).

7. Mission Plan
Study of tropical cyclogenesis, intensification, transition and weakening
Based out of Guam (P3)
Other aircraft include USAF C130 and DLR Falcon
P3: dropsondes, ELDORA and P3DWL
C130: dropsondes
Falcon: dropsondes, DWL, DIAL
Use ferry flights to collect long curtains of wind soundings to test data impact on NWP.
Pax River to West Coast
West Coast to Hawaii
Hawaii to Guam

8. Guam

9. Activity Summary P3DWL in the field from August 4 to October 8, 2008
Total data (ground and airborne) = 171 hours
Flew 18 missions with Tropical Cyclones as target
118 hours of data
Additional flights:
Calibration of other instruments
Ferry flights between bases
Ferry flights USA – Guam – USA (> km)

10. Example of P3DWL observations near a Typhoon
Tropical cyclone Nuri
August , 2008 flight
Flight level ~3000 meters
Downward scanning for wind profiles

13. Flight level winds from P3

14. P3DWL winds at 2100 M

15. P3DWL winds at 1500 M

16. P3DWL winds at 500 M

17. P3DWL winds at 200 M

18. 00007 UTC Dropsonde: (Three horizontal red lines are at 800, 900,
1000 mb). Wind barbs are 5 m/s full, 2.5 m/s for half barb.

20. Dropsonde at 0131, just east of the circulation center:

21. Lidar profile at 013454, number 5
Lidar profile at , number 5. Qualitatively similar to the dropsonde: SSW flow
at lowest levels, southerly flow through deep layer shifting towards E at top of profile

22. Organized Large Eddies

24. ~1500m
~400m

26. Water surface returns
Reasons for water surface returns at >20 degrees include foam, spray and wave tilting of capillary facets
Using data taken with a nadir viewing angle, vertical wave motions can be used to measure wavelengths.
Wave tilt is estimated from height and length of wave. Crest angles of ° are common.

27. Nadir view over water (single shots)

29. TODWL wave measurements with aircraft related corrections
Ground speed = 55 m/s
Sample frequency 80Hz >> .69 m/sample
Wavelength of swell = 200 m
Wavelength of wind waves = 21.5 m
max tilt of wave surface ~ 13 degrees
Maximum vertical wave velocity of 1.9 m/s

30. Expected waves NOAA Buoy 46042 - Monterey Tables winds: 19kts from NW
swell: 2.4 meters; 11.1 seconds; NW
computed wavelength = 192 meters
wind waves: meters; 3.7 seconds; NNW
computed wavelength = 21.4 meters
Tables
17-21 kts > 1.3 m; 5.4 s; 20-30m length

31. Summary
Wind lidar data taken with a 2 um coherent Doppler wind lidar on board the NRL P3 aircraft is now going through final processing.
Preliminary inspection of the data suggests that > 85% useful data collected between surface and 3km; this appears to be the case even when observing near TCs.
Long curtains of wind profiles are available for simulating future space-based DWLs and data impact studies at modeling centers.

32. P3DWL Operators Dan Carre’, Simpson Weather Associates
July ferry flight Pax river to Guam
1 -17 August in Guam
Michael Riemer, Naval Post Graduate School
15 – 31 August
Brian Tang, Massachusetts Institute of Technology
28 – 15 September
CDR Dan Eleuterio, NRL/ONR
13 September – 3 October

33. Acknowledgements
Funding for this research is provided by The Office of Naval Research (Dr. Ronald Ferek) and the Integrated Program Office of the NPOESS (Dr. Stephen Mango).