Retrieval of Three-Dimensional Raindrop Size Distribution Using X-Band Polarimetric Radar Data

D-S. Kim, M. Maki, D-I. Lee
2010 Journal of Atmospheric and Oceanic Technology  
An improved algorithm based on the self-consistent principle for rain attenuation correction of reflectivity Z H and differential reflectivity Z DR are presented for X-band radar. The proposed algorithm calculates the optimum coefficients for the relation between the specific attenuation coefficient and the specific differential phase, every 1 km along a slant range. The attenuation-corrected Z DR is calculated from reflectivity at horizontal polarization and from reflectivity at vertical
more » ... zation after attenuation correction. The improved rain attenuation correction algorithm is applied to the range-height indicator (RHI) scans as well as the plan position indicator (PPI) volume scan data observed by X-band wavelength (MP-X) radar, as operated by the National Research Institute for Earth Science and Disaster Prevention (NIED) in Japan. The corrected Z H and Z DR values are in good agreement with those calculated from the drop size distribution (DSD) measured by disdrometers. The two governing parameters of a normalized gamma DSD, normalized number concentration N W , and drop median diameter D 0 are estimated from the corrected Z H and Z DR , and specific differential phase K DP values based on the "constrained-gamma" method. The method is applied to PPI and RHI data of a typhoon rainband to retrieve the three-dimensional distribution of DSD. The retrieved DSD parameters show reasonable agreement with disdrometer data. The present results demonstrate that high-quality correction and retrieval DSDs can be derived from X-band polarimetric radar data.
doi:10.1175/2010jtecha1407.1 fatcat:d2ky7g3yfnbcndyiz2tbostvea