Simulation of Airborne Radar Observations of Precipitating Systems at Various Frequency Bands

Abstract

This paper addresses the question of the most efficient couple (f, θ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3dB</sub> ) for airborne radar precipitating system observations, where f is the microwave frequency and θ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3dB</sub> is the beamwidth aperture at 3 dB. This problem is of importance. The meteorological hazard in civil aviation is mainly due to convective precipitating systems, particularly hail and strong turbulence areas. A realistic and flexible model of precipitating systems is presented, and simulations of airborne radar observations are performed at the six meteorological frequency bands (S, C, X, K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</sub> , K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> , and W). In this paper, the effect of f and θ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3dB</sub> modification is shown through radar simulations of two precipitating systems. One is a numerical simulation composed of two successive rows of convective towers; the other is inspired from a real mesoscale system, presenting hail-bearing convective towers. It is shown that some (f, θ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3dB</sub> ) couples are better than the one currently used by civil aviation. Notably, C band allows a better description than X band of a meteorological radar scene if the radar antenna size is increased. The model and methodology presented herein are adaptable to ground-based and satellite radars.