Airborne Phased Array RadarAirborne Doppler radar is a critical tool for studying weather and related hazards, especially over rugged terrain or the open ocean where operations are inherently challenging. Major advances in radar technology have paved the way for development of an Airborne Phased Array Radar (APAR) to provide more detailed observations from within these high-impact weather systems (e.g., thunderstorms, hurricanes) as well as enabling the dual-polarization capabilities for microphysical studies not possible from present airborne Doppler radars. An APAR system is currently being designed and developed by NCAR for installation on the NSF/NCAR C-130 aircraft. Four Active Electronically Scanned Array (AESA) panels consisting of a few thousands electronic radar transmitters and receivers and no moving parts will replace the mechanically rotating radar antenna. This will provide more agile scanning strategies and enhanced capabilities for researchers to advance science frontiers.

EOLEarth Observing Laboratory

NCARUCAR

development • deployment • data • discovery

EARTHOBSERVINGLABORATORY

Development project

EOL is managed by the National Center for Atmospheric Research and sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

About APAR

The proposed APAR system consists of four removable, C-band AESA panels strategically mounted on the external fuselage of the NSF/NCAR C-130 aircraft. Two AESAs will be mounted on either side of the fuselage behind the rear personnel doors, the third will be mounted on the top of the fuselage forward of the wing, and the fourth on the rear tail ramp. Each AESA measures approximately 1.8 m x 1.8 m and is composed of ~2,400 active, radiating radar elements. The C-130 nose surveillance radar provides added reflectivity information from directly ahead of the aircraft.

AdvAntAges of APAR

APAR will be a state-of-the-art airborne radar with unique capabilities and complementary to other instruments that can be carried aboard the C-130 aircraft. It will significantly improve our understanding of microphysical processes for raindrops and ice crystals, leading to better estimates of heavy precipitation and potential impacts. The design will be adaptable to other C-130 aircraft operated by many agencies in the United States and other nations, including the U.S. Air Force for hurricane reconnaissance and research.

contacts

APAR Scientist Dr. Wen-chau Lee wenchau@ucar.edu 303.497.8814

APAR Project Manager Dr. Louis Lussier lussier@ucar.edu 303.497.1080

on the Web

www.eol.ucar.edu/instruments/apar

technicAl sPecificAtions

» Frequency: 5.35 GHz – 5.45 GHz » Total Elements per AESA: ~2400 » Beamwidth (El/Az): <2o/<2o » Antenna Gain: ~40 dB » MDR @ 10 km: -13 dBZ

» Peak Transmit Power: ~10 kW » Polarization: Dual Linear » Spatial Resolution @ 10 km: 314 m » Along Track Spacing: 200 m » Pulse Width: 0.5 μs to 40 μs

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