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

Russ Chadwick, Earth System Research Laboratory/OARRandy Johnson, Air Resources Laboratory/OAR

Jim Jordan, Earth System Research Laboratory/OARSandy MacDonald, Office of Oceanic and Atmospheric Research

Louis Wasson, Mississippi State University

WISDOM Intensity Program

Presentation Outline:

WISDOM Intensity ConceptAeroclipper ResultsWind ModelWHISSP DesignWHISSP Field ExperimentConclusions

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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

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.

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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.

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The AeroclipperJ.P. Duvel et al.,BAMS Jan09

Three Subsystems

Helium Balloon

50 m Tether Line

Surface Watercraft

Aeroclipper TrajectoriesGreen line – center of TC Dora 1200z 29Jan to 0000z 06Feb2007

Crosses – Aeroclipper locations 0300z 3Feb

White dots – wind data

Balloon position (Latitude, Longitude and Altitude)Wind speedWind directionBarometric pressureAir temperature Relative humiditySea surface temperatureSolar radiationOther sea surface measurements

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WHISSP Prototype Design Data Collection: Measurements that WHISSP can make above the ocean surface include:

Balloon and Watercraft Response Calculations

Inflated balloon diameter – 1.4 mBalloon and payload mass – 0.3 kgWatercraft mass – 3.0 kgTether line length – 50 mWind speed logarithmic in heightResults for low, medium, high winds

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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)

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Wind Model ConclusionsEntrainment 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.

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2010 WHISSP ExperimentProof 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.

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Balloon during inflation test

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Balloon with SailIntensity Program

Assembled payload housing

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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.

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WHISSP LaunchIntensity Program

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WHISSP Test FlightsIntensity Program

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.

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WISDOM Intensity 2010-12 Program:Completed study to develop a prototype

WHISSPESRL, ARL, UAS and NHC partnering on in-

house OAR effortTested experimental model in 2010 –

demonstrated proof-of-conceptEvaluate alternative SATCOM and payload

optionsTwo 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

Aeroclipper WindsEntrainment phase data

Zero angle is TC Dora’s course

Black crosses show eyewall

Response to Low Wind Conditions

Response to Medium Wind Conditions

Response to High Wind Conditions

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

Wind Model based on Aeroclipper DataTangential 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