Mid-scale RI-2: Airborne Phased Array Radar (APAR)

This award supports the final development, testing, and implementation of the Airborne Phased Array Radar (APAR), which will provide a generational leap in severe storm and climate research. Operated by the National Center for Atmospheric Research (NCAR), APAR will make measurements of clouds and severe storms all over the world, including over oceans, rough land, and forested regions, which are mostly unreachable by conventional radar systems thereby eliminating a data gap in atmospheric science research.

As the next-generation operational weather observing capability for the United States, APAR meets a critical need for new weather observations. With new capabilities to see deep into the three-dimensional structure of intense storms and cloud systems, crucial new insights are gained into the distribution of water vapor, precipitation, and associated radiative processes that govern Earth's energy balance.

APAR measurements will be used to test predictions about severe weather, including tropical cyclones, tornadoes, damaging straight-line winds, hail, and flash flooding, and allow researchers to record the complex and changing lifecycle of severe systems. APAR will be a requestable community facility in the GEO /AGS Lower Atmosphere Observing Facilities pool.

The implementation and subsequent operation of APAR will offer the research community access to high-resolution radar data for engineering and scientific analyses, and help mitigate threats and risks to transportation, forestry, agriculture, economy, and health. Other innovations include mapping out characteristics of insect/bird migrations over thousands of kilometers and the development of innovative software solutions.

Funding for APAR will enable significant opportunities for training a diverse workforce by incorporating educational and training opportunities that will draw from underrepresented and minority student, educator, and researcher populations. Multi-faceted and -lingual outreach and education events and products are planned to reach a broad and diverse audience through the NCAR Explorer Series.

APAR will be the world’s first phased array C-band (5 cm wavelength), dual-Doppler, dual-polarization radar with fast-scan agility to be carried on an aircraft. It will consist of four removable active electronically scanned array antennas that will be mounted on the fuselage of the NSF/NCAR C-130. The engineering breakthroughs required to implement APAR push the boundaries of current phased-array-radar technology, including antenna performance never previously achieved and tools and techniques (including signal processing to derive a multitude of storm characteristics) to harvest the copious volumes of data to be collected.

Compared to ground-based platforms which must alternate between data collection and transit modes, APAR will be able to obtain continuous three dimensional, very high spatiotemporal resolution observations of storm kinematics and microphysical cloud properties.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.