Using Disdrometer Measured Raindrop Size Distributions to Establish Weather Radar Algorithms

Relations to estimate, from radar measurements, precipitation (e.g., rainfall rate or liquid water content), and attenuation (specific attenuation) parameters are widely used in radar meteorology. Such relations are often derived by applying regression methods, simulated target parameters, and radar measurements simulated from datasets of drop size distributions and using additional microphysical and electromagnetic assumptions. Datasets are determined both by theoretical considerations and from experimental measurements collected throughout the year by disdrometers, although the latter are considered more representative of a specific climatology. However, instrumental errors can affect these results. Different values of the coefficients resulting from different disdrometers are presented and discussed with reference to disdrometer measurements available in the Rome area and for the C-and X-band dual polarization radar.