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

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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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Community Airborne Platform Remote-sensing
Interdisciplinary Suite (CAPRIS) on C-130
Instrument Science
Aairborne 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
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CAPRIS Airborne Centimeter Radar Configurations

• Four C-band active element scanning array (AESA)
  conformal antennas
• Beam width 2.1x1.6/ 2.2x2.3
• Sensitivity -4 dBZ at 10 km
• Gate spacing 150 m
• Dual Doppler (V, sv)
• 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
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Possible CAPRIS Radar Positions on C-130
Upper AESA
W, Ka band Pod
Starboard AESA
Port AESA
Rear AESA
C-130 front view
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Composite Surveillance Scan
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Resolution Makes A Difference!
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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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The NSF Opportunity

• 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

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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
(jmoore_at_ucar.edu) Wen-Chau Lee
(wenchau_at_ucar.edu) Visit the website http//www
.eol.ucar.edu/development/capris/
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END
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X-Pol Reflectivity
S and X-band Radar Observations
Total attenuation
S-Pol
Not good correction
X-Pol corrected.
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AESA Characteristics
PARAMETER X-Band C-Band
Wavelength 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) 0.725? x 0.575? 0.725? x 0.575?
Elements/Panel (w x l) 10 x 16 10 x 16
Panels 16 16
Total Elements 2560 2560
First Sidelobe lt -25 dB lt -25 dB
Cross-Pol Isolation gt 30 dB gt 30 dB
Noise Figure 3.5 dB 3.5 dB
Transmit Power (peak) 2.9 kW _at_ 10 duty 2.9 kW _at_ 10 duty
EIRP (worst case) 90 dBm avg. 90 dBm avg.
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CM-Wave Radar Performance
X-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 _at_ 10 km -6.2 dBZ _at_ 10 km
Sensitivity (single hit, 10 mm/hr rain) -6.2 dBZ _at_ 10 km -5.8 dBZ _at_ 10 km
Polarization Dual H or V Dual H or V
140 deg/sec scan rate