NASA D3R linear depolarization ratio observations and a new estimation technique

The polarimetric radar parameter, linear depolarization ratio (LDR), provides microphysical insight into a scattering volume, particularly for mixed-phase and ice particles. A new estimator for improved estimation of LDR is presented. The NASA dual-frequency, dual-polarization, Doppler radar (D3R), which was recently upgraded to support operational linear depolarization ratio observations, was used as a testbed for evaluation of the new estimator. With D3R's Ku-band observations, the new LDR estimator is compared to conventional estimators and it is demonstrated that the new estimator is insensitive to attenuation, a number of radar system biases, and has increased immunity to noise for low SNR observations.