An Attempt to Estimate Differential Reflectivity Bias Using Volume Scan Dataset Obtained by C-Band Polarimetric Radar on Board R/V Mirai

An alternative method to estimate the differential reflectivity (ZDR) bias is proposed. The method collects data bins with "weak echo" by the liquid hydrometeor, which theoretically should be spherical (not oblate) to result in a ZDR of similar to 0 dB, to calculate the averaged ZDR as the bias. The obtained results are comparable to those from traditional "birdbath" scans in hourly data to prove the validity. The present method can be used to better sample the temporal variation, without operating special scans, such as birdbath scans. The supplemental method for the short-pulse region, when it was difficult for the weak-echo method to directly obtain the valid result, is also demonstrated.