Simulation of Polarimetric Phased Array Weather Radars

Abstract

Polarimetric phased array radars (PPARs) are a rapidly developing area of research interest in weather radar. However, they present intrinsic challenges for calibration and operation. Foremost among these are the adverse effects of copolar radiation pattern mismatch as well as cross-polar fields on polarimetric measurement accuracy. Characterization of the impact these effects have on weather radar observations and the effectiveness of proposed methods for mitigation of those impacts can be time-consuming and costly if conducted using radar hardware. Furthermore, few operational PPARs exist to serve as testbeds. Alternatively, the effects of copolar and cross-polar fields can be studied using numerical simulations. In that regard, this work outlines a simulation method that allows for the characterization of PPAR performance and the prototyping of techniques to mitigate cross-polar biases. To achieve this, a simulation volume is populated by thousands of scattering centers, whose movement and scattering characteristics at any point in space and time are governed by a high-resolution numerical weather prediction model. Each of these scattering centers has its own individually calculated Doppler spectrum in both the horizontal (H) and vertical (V) polarizations. These spectra are used to determine instantaneous scattering parameters that are combined with a highly flexible radar system model in order to compose time-series signals in H and V. This simulation method is used to evaluate and compare the performance of several bias mitigation techniques that have been previously proposed.