Simulation of radar reflectivity fields: Algorithm formulation and evaluation

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Abstract
A hybrid stochastic physics‐based and polarization‐diverse radar reflectivity simulation procedure for rainfall studies is described. The procedure begins with the generation of two‐dimensional rainfall intensity fields from a space‐time stochastic model with a statistical parametrization of drop‐size distribution. The two‐dimensional fields are complemented with a vertical structure of hydrometeors by choosing a precipitation cloud type model, which results in size, shape, and phase (mixed or single) distribution at discrete elevations. Given these three‐dimensional fields, the sampling volume integration process involved in radar measurements is simulated to give the radar‐observed parameters. Effects such as antenna beam pattern, horizontal and vertical gradients, atmospheric gases, and rain attenuation are represented. The radar observables are corrupted with a random measurement error to represent the radar hardware system noise and other sources of uncertainty. The simulated radar reflectivities are qualitatively evaluated using actual radar data. The simulator is a useful tool for engineers and hydrometeorologists in the study of radar‐rainfall measurement and estimation errors and their effects.