Justyna Nicinska, Office of Oceanic and Atmospheric Research (OAR)

1. WISDOM Intensity Program WHISSP - Weather/Hurricane In-situ Sea Surface Probe:Goal: Continuous Observing within the Hurricane EyeMarch 1, 201165th Interdepartmental Hurricane Conference Justyna Nicinska, Office of Oceanic and Atmospheric Research (OAR) Russ Chadwick, Earth System Research Laboratory/OAR Randy Johnson, Air Resources Laboratory/OAR Jim Jordan, Earth System Research Laboratory/OAR Sandy MacDonald, Office of Oceanic and Atmospheric Research Louis Wasson, Mississippi State University

2. Intensity Program Presentation Outline: • WISDOM Intensity Concept • Aeroclipper Results • Wind Model • WHISSP Design • WHISSP Field Experiment • Conclusions

3. WISDOM- started in 2008 with aim of designing a system for data collection in the synoptic environment, targeting remote areas of the ocean, days ahead of a hurricane’s landfall 3

4. Intensity Program • Observing System Need: Providing continuous data in the eye of a tropical cyclone • Minimal data is presently available in the eye of a Tropical Cyclone • Concept for WISDOM Intensity work came from the French Aeoroclipper study- • Two blimps successfully reported back data from the eye of a TC in the Indian Ocean. • WISDOM-aim to develop a simpler, low cost version of the Aeroclipper.

5. Intensity Program • Research Needs: • Currently pressure data is available for about 30% of Atlantic storms and 5% of Pacific Storms. • Filling existing data gaps may lead to improved intensity forecasting. • Data will help to understand and characterize the evolution of the energy content of the low marine boundary-layer inflow to hurricanes • its relationship with hurricane intensity changes, the influence of ocean temperature, and estimates of surface fluxes.

6. The AeroclipperJ.P. Duvel et al.,BAMS Jan09 Three Subsystems • Helium Balloon • 50 m Tether Line • Surface Watercraft

7. Aeroclipper Trajectories • Green line – center of TC Dora 1200z 29Jan to 0000z 06Feb2007 • Crosses – Aeroclipper locations 0300z 3Feb • White dots – wind data

8. Intensity Program WHISSP Prototype Design Data Collection: Measurements that WHISSP can make above the ocean surface include: • Balloon position (Latitude, Longitude and Altitude) • Wind speed • Wind direction • Barometric pressure • Air temperature • Relative humidity • Sea surface temperature • Solar radiation • Other sea surface measurements

9. Intensity Program Balloon and Watercraft Response Calculations • Inflated balloon diameter – 1.4 m • Balloon and payload mass – 0.3 kg • Watercraft mass – 3.0 kg • Tether line length – 50 m • Wind speed logarithmic in height • Results for low, medium, high winds

10. WHISSP Response to Low –Medium-High Wind Conditions

11. Intensity Program Key Points for the Simple Wind Model • For these parameters, watercraft travels at about 60% wind speed over wide range of wind speeds. • So, compare trajectories of a 60% unit (blue) with those of a 30% unit (yellow). • Comparing three launch pairs inside the hurricane and one launch pair from outside the hurricane. • (inside is less than 47 km radius out from the center)

12. Simple model based on Aeroclipper data: Trajectories over 24 hours for two WHISSP balloons released into the upper right quadrant of the northward moving hurricane. Blue trajectory is for a WHISSP capable of moving at 60% of the wind and the yellow trajectory is for movement at 30% of the wind.

13. Trajectories over 24 hours for two WHISSP balloons released ahead of the center of the northward moving hurricane. Blue trajectory is for a WHISSP capable of moving at 60% of the wind and the yellow trajectory is for movement at 30 % of the wind.

16. Intensity Program Wind Model Conclusions • Entrainment into hurricane is not as easy as it may appear. • Starting inside Radius of Maximum Winds (RMW-red line) increases chances of entrainment, but does not guarantee it. • Unit more responsive to wind has greater chance of entrainment.

17. Intensity Program 2010 WHISSP Experiment • Proof of Concept with low cost experimental model: • Balloon – 6 foot diameter balloon carrying a WISDOM 100 gram payload. • Tether line – 164 ft. light plastic string. • Watercraft – 40 ft of half inch and one inch silicone tube • Launched four units in December 2010.

18. Intensity Program Balloon during inflation test

19. Intensity Program Balloon with Sail

20. Intensity Program Assembled payload housing

21. Intensity Program WHISSP Experimental Model Trial • Four WHISSP experimental were models launched from Tybee Island GA December 3-4, 2010. •  Balloons 9 and 12 were launched on December 3rd and balloons 35 and 38 were launched on December 4th.  In chronological and numerical order the balloon lift for the balloons was -60g, -180g, -300g, and -420g.  The negative sign indicates that the weight of the ballast hose attached to the balloon is that many grams heavier than the net lift of the balloon. • In all of the launches the balloon ultimately lifted the ballast hose entirely out of the water and rose to higher altitudes rather than staying at the planned 150 feet.  • About one week after the launch 2 out of 4 balloon tags continued reporting data and were floating about 50 meters above the sea surface.

22. Intensity Program WHISSP Launch

23. Intensity Program WHISSP Launch

24. Intensity Program WHISSP Test Flights

25. Graph of Altitude for WHISSP units showing all data (including error contaminated) received at the ground station between December 3 and December 16, 2010.  While the altitude data cannot be assumed to be valid, this does show that all of the units operated for at least a day and that 3 of the 4 operated for more than a week and one operated for nearly 2 weeks. Intensity Program

26. WISDOM Intensity 2010-12 Program: • Completed study to develop a prototype WHISSP • ESRL, ARL, UAS and NHC partnering on in-house OAR effort • Tested experimental model in 2010 – demonstrated proof-of-concept • Evaluate alternative SATCOM and payload options • Two design concepts to evaluate in addition to WHISSP (USV and “beach ball) • Continue engineering efforts to develop advanced model of the WHISSP for data collection in Hurricane Eye • Field testing in Hurricane Eye by 2011-2012 • THANK YOU! 26

27. BACK UP SLIDES

28. Aeroclipper Winds • Entrainment phase data • Zero angle is TC Dora’s course • Black crosses show eyewall

29. Response to Low Wind Conditions

30. Response to Medium Wind Conditions

31. Response to High Wind Conditions

32. Concept for airborne deployment • Balloon – one to three meter plastic balloon with measurement electronics and GPS • Tether line – air dielectric coax cable for tether, helium path up, power path up, data path down • Watercraft – batteries, computer, GPS, satellite communications, helium tank

34. Wind Model based on Aeroclipper Data • Tangential wind as function of radius r W(r) = K r exp(-r/RMW) K chosen so W(r)=40 m/s when r=RMW, the Radius of Max Winds, red circles for 47 km. • Radial winds inward at 25% of tangential winds • Upper level steering winds pushing hurricane northward at 12 m/s