Attenuation in Rain for X- and C-Band Weather Radar Systems: Sensitivity with respect to the Drop Size Distribution

Abstract This paper is devoted to a sensitivity study of the equation describing attenuation effects in rain for ground-based weather radar systems operating at X- or C-band wavelengths. First, the so-called attenuation equation, also termed the HB solution or HB algorithm in reference to the well-known paper by Hitschfeld and Bordan, is recalled. A procedure aimed at obtaining consistent relations between average values of the equivalent reflectivity factor Ze, the attenuation coefficient k, and the rain rate R as function of two parameters of the drop size distribution (DSD) is also presented. Then, a numerical simulation framework based on a simple description of rainfall characteristics and accounting for some of the radar measurement features is proposed to test the ability of the HB algorithm to perform attenuation correction of hypothetical rain-rate profiles. In a first step, the well-known instability of the solution is illustrated. For instance, it is shown that, even in the absence of radar cal...