Airborne Phased Array Radar (APAR): The Next Generation of Airborne Polarimetric Doppler Weather Radar

Wen-Chau Lee

National Center for Atmospheric Research Earth Observing Laboratory (NCAR)

Tuesday, Feb 13, 2024, 2:00 pm MT
DSRC Room GC402

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Abstract

The National Science Foundation (NSF) of the United States approved the Airborne Phased Array Radar (APAR) Mid-scale Research Infrastructure-2 proposal in 2023 to develop the next generation airborne polarimetric, Doppler weather radar mounted on the NSF/National Center for Atmospheric Research (NCAR) C-130 aircraft. Polarimetric measurements are not available from current airborne tail Doppler radars. The APAR system will consist of four removable C-band active electronically scanned arrays (AESA) strategically placed on the fuselage of the aircraft. Each AESA measures approximately 1.5 x 1.5 m and is composed of 2368 active radiating elements arranged in a total of 37 line replaceable units (LRU). Each LRU is composed of 64 radiating elements that are the building block of the APAR system. The development will take 5 years to be completed in summer 2028. APAR adopts a phased approach as an active risk assessment and mitigation strategy. Both the NSF and the National Oceanic and Atmospheric Administration have funded the APAR project for risk reduction activities in the past 5 years.

This talk will update current progress and accomplishments of APAR during the first year of the development, including the activities of the university and private industry partners and the engagement of collaboration with research and operational communities.

One of the challenges with developing new instrumentation is the unknown performance characteristics of the instrument, the subsequent unknowns in uncertainty in measurements, and strategies to analyze these data. The APAR Observing Simulator (AOS) was developed to understand APAR's measurement capabilities for high-impact weather events. Using Cloud Model 1 (CM1) and Weather Research and Forecasting (WRF) model output to provide various storms of interest and their surrounding environments, simulated NCAR C-130 flights are operated within the model space. Radar moments are determined using the Cloud Resolving Model Radar Simulator (CR-SIM). The output can be examined directly or passed through additional tools to analyze various aspects of the data collected during each flight. AOS will be a critical component in developing the next generation APAR analysis software.

The initial design of the next generation APAR analysis software will also be discussed.