Considerations for Dual-Polarization Measurements from an Airborne Phased Array Doppler Weather Radar

Airborne Phased Array Radar (APAR) is a weather radar deployed on a C-130 aircraft operated by National Center of Atmospheric Research (NCAR) that has the ability of electronic scanning and to obtain measurements of dual-polarization and Doppler signatures from storms. Dual polarization observation with electronic beam steering off-boresight needs careful calibration and planning. This is because phased array antenna changes its antenna properties as a function of steering angles, while present in all observations, the dual-polarization measurements are the most sensitive. Furthermore, these effects depend on the design and structure of the array. This work explores the properties of APAR system, with an emphasis on the considerations for dual-polarization measurements.