Modeling weather radar surveillance over complex terrain

Minimizing terrain blockage is a basic consideration when assessing the convenience of weather radar sites. This work presents a numerical model for simulating surveillance coverage of weather radars under mountain terrains. A common unrealistic approximation in this type of computations is to assume that the vertical gradient of air refractive index is approximately constant in the height interval of interest. Instead, this work considers actual changes in refractive index by discretizing its vertical profile in small finite intervals. In this new approach, the refractive index is then approximated to a constant only within finite intervals (piece-wise). As input, the simulation uses a high-resolution terrain digital model, the weather radar parameters, and radiosonde observations of the vertical profile of temperature, pressure and vapor mixing ratio. Precipitation observations from a C-band weather radar, located at Mount Sicker (British Columbia), are used to validate the model outputs.