03/06/2007 ihc new orleans1 potential applications of the proposed phase array doppler radar on the...

03/06/2007 IHC New Orleans

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Potential Applications of the Proposed Phase Array Doppler Radar on the NSF/NCAR C-130 in Hurricane

Reconnaissance

61st Interdepartmental Hurricane Conference

NCAR Earth Observing Laboratory

Wen-Chau Lee, J. Vivekanandan, Eric Loew, James Moore


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Introduction• 2/3/07, Jeff Hawkins message to Tropical-storms list: “ …Which

highlights one of my favorite subjects: the need for inner-core aircraft penetrations in the WPAC to help validate satellite intensity/structure algorithms that have zip to go on since 1993 in the most active TC basin.”

• Wen-Chau Lee: “Wouldn't it be nice to have airborne Doppler radar to go with the recon in WPAC? The dataset will be able to validate the microwave sensors on satellite and give a more definite 3D structure of the typhoon (wind and precipitation) than those can be provided by the insitu measurement.”

• Jeff: “Which aircraft are we talking about here?”• Wen-Chau: “The concept of CAPRIS on NSF/NCAR C-130 and its

potential applications on Air Force C-130. … Just realized that you are the session co-chair of my concept paper at IHC next Tuesday.”

• Jeff: “Yap, see you there.”


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Current Hurricane Reconnaissance Capability

Central Pressure

Insitu (u,v,w,T, Td, etc)

Expendable

Remote sensors

3-D Dual-Doppler (u, v, w, and Z)

Cloud Physics(in situ)

Cloud Physics(polari-metric radar)

Air Force C-130s

Yes Yes Dropsonde SFMR No No No

NOAA WP-3Ds

yes Yes Dropsonde, AXBT, AXCP, AXCP, Drifting Buoys

SFMR,C-SCAT

Yes Yes No

NOAA Gulfstream IV

No Yes Dropsonde No Yes (soon)

No No


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Why Airborne Dual-Doppler Radar Capability Is Critical in Hurricane Reconnaissance, Operations, and

Research It is currently the only means to probe 3-D

hurricane inner core kinematic structures at a spatial resolution ~1 km

Hurricane inner core is the critical region governing hurricane evolution and intensity change

Basic understanding of hurricane inner core dynamics will improve numerical model physics and lead to better prediction

Improved description on hurricane inner core structure by assimilating Doppler radar data into hurricane model has been identified as one of the critical paths toward improving intensity forecast


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How About Polarimetric Radar Data?

• Polarimetric radar data combined with fuzzy logic technique can identify particle type, shape, rain rate, etc. in precipitation systems.

• Microphysical information in TC has been obtained by insitu measurements only at flight levels.

• Only a handful of TCs have been sampled by ground-based polarimetric radars.

• This is an area that has not been explored in TCs.


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Instrument ScienceAairborne polarimetric centimeter Doppler Radar – C or X bands

Hurricane, severe storms, Convection initiation, tropical meteorology. Kinematics and microphysical processes.

Pod based dual-wavelength, dual-polarization, millimeter wave Doppler radar – W, Ka Bands

Cloud and drizzle microphysics, ice microphysics, and cloud radiation properties

H2O Differential Absorption Lidar (DIAL), O3 DIAL, Doppler Wind Lidar (UTLS and PBL systems) CO2 DIAL, Vegetation Canopy Lidar

Climate change, fluxes and transport of water vapor, ozone, and pollutants from boundary layer to UTLS, gravity waves

Community Airborne Platform Remote-sensing

Interdisciplinary Suite (CAPRIS) on C-130


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CAPRIS Airborne Centimeter Radar Configurations

• Four C-band active element scanning array (AESA) conformal antennas

– Beam width 2.1°x1.6°/ 2.2°x2.3° – Sensitivity -4 dBZ at 10 km– Gate spacing 150 m

• Dual Doppler (V, σv)• 2 x along track resolution (~200 m) of

current ELDORA system due to scanning agility, simultaneous beams from all four antennas, and slower polarimetric scanning

• Dual polarization H,V linear– ZH, ZDR, KDP, RHOHV

Antenna Size:

~2.0 m X 1.5 m

~2000 elements

Radiators16:1combiner

Analog TDU

16:1 combiner+ filter bank

+ digital T/R chip

BuildingBlock

T/R chips


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Rear AESA

Upper AESA

Starboard AESA

Port AESA

W, Ka band Pod

C-130 front view

Possible CAPRIS Radar Positions on C-130

Composite “Surveillance” Scan

Resolution Makes A Difference!

Vertical X-section in Hurricane Rita at 500 m Resolution (From John Gamache 3D

Analysis)

Eye


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Potential Applications to Hurricane Reconnaissance and Research

The AESA radar system can be installed on Air Force C-130s to collect high-resolution 3-D inner core kinematic and microphysical structures during all reconnaissance missions

Real-time dual-Doppler winds can be transmitted back to NHC and Qced Doppler radar radial velocities and polarimetric data can be transmitted to NCEP for radar data assimilation in hurricane models for every TC that has recon flights

Generate expanded hurricane database for the Atlantic basin

Impact the operation and research community - validation of satellite products, process studies, design observing strategy, …


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Mid-Size Infrastructure for Atmospheric Sciences

ATM maintains a mid-size infrastructure account that can be used to build and/or acquire community facilities.

Several groups are competing for available funds

General Considerations (highlights)• Community facility• It is expected to take five years to develop CAPRIS cm radar

after NSF approval. • Partnerships with university, federal, private, or international

institutions are encouraged.

EOL has been encouraged to submit a White-paper for CAPRIS

• Key time for community comment and advice on present concepts

• Revised White Paper Document due to NSF Mid March 2007• NSF will evaluate all white papers and invite several projects to

submit final proposal in Fall 2007

The NSF Opportunity


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Partnership and Collaboration Opportunities

• CAPRIS has established a strategic partnership with MIT/Lincoln Laboratory to develop the AESA component.

• Lincoln Laboratory is developing a Multifunction Phased Array Radar (MPAR), sponsored by FAA, NWS and DoD/DHS, to replace and consolidate existing radars operated by FAA, NWS and DoD.

• MPAR will provide terminal-area and long-range aircraft surveillance and weather measurements.

• AESA technology allows 3-D volumetric coverage of hurricane inner core kinematic and microphysical structures.

• There is a unique opportunity to leverage these complementary developments for the benefit of hurricane reconnaissance, operation, and research.


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Questions and Comments

For further information, contact:Jim Moore ([email protected])Wen-Chau Lee ([email protected])

Visit the website:http://www.eol.ucar.edu/development/capris/

mailto:[email protected]





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END


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S-Pol

X-Pol corrected.

X-Pol Reflectivity

Total attenuation

Not good correction

S and X-band Radar Observations


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AESA CharacteristicsPARAMETER X-Band C-BandWavelength 3.2 cm 5.045 cm

Dimensions (w x l) 0.93 m x 1.18 m 1.46 m x 1.86 m

3dB Beamwidth (broadside) 2.1° x 1.6° 2.1° x 1.6°

3dB Beamwidth (20° Az, 45° El)

2.1° x 1.6° 2.1° x 1.6°

Gain (broadside) 38 dBi 38 dBi

Gain (20° az, 45° el) 36 dBi 36 dBi

Element Spacing (w x l) 0.725λ x 0.575λ 0.725λ x 0.575λ

Elements/Panel (w x l) 10 x 16 10 x 16

Panels 16 16

Total Elements 2560 2560

First Sidelobe < -25 dB < -25 dB

Cross-Pol Isolation > 30 dB > 30 dB

Noise Figure 3.5 dB 3.5 dB

Transmit Power (peak) 2.9 kW @ 10% duty 2.9 kW @ 10% duty

EIRP (worst case) 90 dBm avg. 90 dBm avg.


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CM-Wave Radar PerformanceX-Bands C-Bands

Beam Width (nominal)

2.76˚ x 1.76˚

2.76˚ x 1.76˚

Along Track Spacing **

75 m 75 m

Range Resolution

150 m 150 m

Sensitivity (single hit, no attenuation)

-8.6 dBZ @ 10 km

-6.2 dBZ @ 10 km

Sensitivity (single hit, 10 mm/hr rain)

-6.2 dBZ @ 10 km

-5.8 dBZ @ 10 km

Polarization

Dual: H or V Dual: H or V

Min Detectable Reflectivity(10 mm/hr Rain)

-35.0

-25.0

-15.0

-5.0

5.0

15.0

0 10 20 30 40 50 60

Range (km)

dBZ

AESA X-Band AESA C-Band ELDORA

** 140 deg/sec scan rate

03/06/2007 ihc new orleans1 potential applications of the proposed phase array doppler radar on the...

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