Airborne Phased Array Radar (APAR) is an advanced atmospheric system being developed in part to replace the expired, X-band Electra Doppler radar (ELDORA). Preliminary design specifications suggest the proposed APAR will meet or exceed ELDORA's sensitivity, spatial resolution and Doppler measurement accuracies and it will also acquire dual-polarization measurements.

APAR, currently under design by NCAR/EOL, consists of four removable C-band Active Electronically Scanned Arrays (AESAs) mounted on the top, both sides, and the cargo ramp of the NSF/NCAR C-130 aircraft. Each AESA is approximately 1.8 m x 1.8 m in size and is made up of ~2,400 transmitting/receiving antenna elements with dual-polarimetric capabilities. The dual-polarimetric capabilities of APAR, in addition to inherent beam agility associated with electronic steering, will provide more flexible scanning strategies and enhanced measurement capabilities.

APAR’s unique capabilities will open new research frontiers in Earth Systems Sciences and high-impact weather events. APAR will enable scientists to advance knowledge about the formation and evolution of societally disruptive weather and environmental conditions leading to it. The transformative remote sensing concept of the APAR will enable improved prediction and predictability, via assimilation of APAR data into numerical weather models, ultimately leading to improved weather alerts to the public.