Transcript Document 7333998

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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03/06/2007 IHC New Orleans
Introduction
•
•
•
•
•
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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
DualDoppler
(u, v, w,
and Z)
Cloud
Cloud
Physics Physics
(in situ) (polarimetric
radar)
Air Force
C-130s
Yes
Yes
Dropsonde
SFMR
No
No
No
NOAA WP3Ds
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
Aairborne polarimetric centimeter
Doppler Radar – C or X bands
Science
Hurricane, severe storms,
Convection initiation, tropical
meteorology. Kinematics and
microphysical processes.
Pod based dual-wavelength, dualCloud and drizzle microphysics, ice
polarization, millimeter wave Doppler microphysics, and cloud radiation
radar – W, Ka Bands
properties
H2O Differential Absorption Lidar
(DIAL), O3 DIAL, Doppler Wind
Lidar (UTLS and PBL systems) CO2
DIAL, Vegetation Canopy Lidar
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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 2.1°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
Building
Block
Antenna Size:
~2.0 m X 1.5 m
16:1 combiner
+ filter bank
+ digital T/R chip
~2000 elements
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Analog TDU
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IHC New Orleans
16:1
T/R chips
combiner
Possible CAPRIS Radar Positions on C-130
Upper AESA
W, Ka band Pod
Starboard
AESA
Port AESA
Rear AESA
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C-130 front view
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Composite “Surveillance” Scan
Resolution Makes A
Difference!
Vertical X-section in Hurricane Rita at 500 m
Resolution (From John Gamache 3D Analysis)
Eye
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 ([email protected])
Wen-Chau Lee ([email protected])
Visit the website:
http://www.eol.ucar.edu/development/capris/
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END
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S and X-band Radar Observations
Total attenuation
S-Pol
Not good correction
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X-Pol
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Orleans
X-Pol Reflectivity
AESA Characteristics
PARAMETER
X-Band
C-Band
3.2 cm
5.045 cm
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
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
2.9 kW @ 10% duty
2.9 kW @ 10% duty
90 dBm avg.
90 dBm avg.
Wavelength
Dimensions (w x l)
Panels
Transmit Power (peak)
EIRP (worst case)
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CM-Wave Radar Performance
Beam Width
(nominal)
Along Track
Spacing **
Range
Resolution
X-Bands
C-Bands
2.76˚ x
1.76˚
2.76˚ x
1.76˚
Min Detectable Reflectivity
(10 mm/hr Rain)
15.0
75 m
75 m
5.0
150 m
150 m
-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
dBZ
Sensitivity
(single hit,
no
attenuation)
-5.0
-15.0
-25.0
-35.0
0
Polarization
Dual: H or V
10
Dual: H or V
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30
40
50
Range (km)
AESA X-Band
** 140 deg/sec scan rate
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AESA C-Band
ELDORA
60