Calibrating LAWR weather radar using laser disdrometers

Estimation of the radar reflectivity from Local Area Weather Radars (LAWR) is investigated. Normally, the LAWR system operates with the Dimensionless Radar Output (DRO) instead of dBZ, because the absolute scaling to dBZ is unknown for the LAWR. A transformation methodology is proposed for LAWR DRO–dBZ conversion. The method applies dBZ observations from ground based disdrometers. The paper illustrates the possibility of establishing a direct relationship between the LAWR DRO estimates and the physical radar reflectivity of the precipitation. Also, rain intensity estimate from the LAWR system, by means of the Marshall–Palmer relation, is conducted nonlinearly from the DRO estimate. This diverges from prior investigations and applications of the LAWR system, which typically rely on a linear assumption between the rain intensity and the LAWR DRO.