Rainfall rate and microphysics retrievals from mobile X-band polarimetric radars

This study synthesizes results from field campaigns in a wide array of settings (i.e., Appalachian Mountains in North Carolina during IPHEX, Cevennes-Vivarais region in southeast France during HyMeX, Italian Alps, Rome, and Athens). In each deployment, disdrometers and rain gauges are used to evaluate 1) attenuation-corrected radar moments, 2) drop size distribution (DSD) parameters, and 3) rainfall rates using a single algorithm called SCOP-ME (self consistent with optimal parameterization and rain microphysics estimation algorithm) (Kalogiros et al., 2013). Despite the diversity of geographical settings and even different radars used in the field campaigns, the algorithm provides consistent results.

The SCOP-ME algorithm is based on relations valid at the theoretical Rayleigh scattering limit corrected by multiplicative rational polynomial functions of reflectivity-weighted raindrop diameter to approximate the Mie character of scattering at these electromagnetic frequencies. It is an iterative, self-consistent algorithm with minimal parameterization error, which was developed using T-matrix scattering simulations for a wide range of DSD parameters and variable raindrop axis ratios. In addition, a correction for vertical profile of reflectivity as well as rainfall estimation during stratiform type of rain is applied to PPI scans. This algorithm is based on the detection of bright band using the co-polar correlation coefficient and the average apparent vertical profile estimated in each PPI scan. This presentation will provide details on the algorithm as well as an analysis of the corrected radar variables, DSD retrievals, and rainfall rate estimates in each of the field campaigns.

Kalogiros, J. M. N. Anagnostou, E. N. Anagnostou, M. Montopoli, E. Picciotti, and F. S. Marzano, (2013): “Optimum estimation of rain microphysical parameters using X-band dual-polarization radar observables,” IEEE Trans. Geosci. Remote Sens, 51, 5, 3063- 3076, DOI: 10.1109/TGRS.2012.2211606