APAR Science Drivers

SCIENCE NEED

Advancing understanding and improving prediction of high-impact weather events and representation of precipitation, clouds, and cloud processes in Earth System models remain at the forefront of atmospheric science research. An airborne Doppler radar is a critical tool for studying Earth Systems Science and high-impact weather systems, especially in hard-to-reach areas such as open ocean and complex terrain where ground-based radars operate is impossible or challenging. The National Science Foundation (NSF) research community has repeatedly identified urgency in developing the next generation of airborne Doppler radars not only to close the capability gap in airborne remote sensing of precipitating systems but also to provide remote sensing observations at wavelengths capable of penetrating deeper into heavy precipitation and with dual-polarimetric capabilities for microphysical retrievals and agile scanning. To address this acute community need, the Earth Observing Laboratory (EOL) at the National Center for Atmospheric Research (NCAR), through a partnership with the National Oceanic and Atmospheric Administration (NOAA) and university and industry collaborators, proposes to implement the dual-polarimetric, dual-Doppler Airborne Phased Array Radar (APAR) on the high-endurance, long-reach NSF/NCAR C-130 research aircraft. APAR will be the first airborne, polarimetric Phased-Array Radar (PAR) that has the ability to collect research-quality weather observations. Once operational, APAR will be collecting unprecedented observations of precipitation processes around the globe.

Significant advances in radar technology have paved the way for developing an Airborne Phased Array Radar (APAR) system that can provide unprecedented detailed concurrent observations of the dynamics and microphysics of high-impact storms, such as hurricanes and mesoscale convective systems. The APAR system is different from previous radars that NCAR/EOL has developed or operated (i.e., Electra Doppler Radar (ELDORA), HIAPER Cloud Radar (HCR) as it uses Phased Array Radar (PAR) technology. APAR does not rely on a single mechanical rotating dish and single high-powered transmitter and receiver. Instead, the APAR will incorporate thousands of low-power miniature TRMs and elements mounted on the exterior of the NSF/NCAR C-130.