Alexander R. Bestugin, Maxim B. Ryzhikov, Yuliana A. Novikova, Irina A. Kirshina

 Saint Petersburg State University of Aerospace Instrumentation (SUAI) (St. Petersburg, Russia) 

 fresguap@mail.ru,  maxrmb@yandex.ru,  Nov-Jliana@yandex.ru,  zlata@aanet.ru

Previous theoretical studies of the authors and the practice of using weather radars at low altitudes show that the assessment of the danger of thunderstorms and turbulence is particularly influenced by the presence of re-reflections from the earth's surface along the side lobes of the directional pattern in the lower hemisphere. The efficiency of synthesis of asymmetric directional patterns in phased array antennas is proved, which reduces the probability of forming false dangerous areas of thunderstorms and turbulence on the radar display. The influence of re-reflections from the ground on the formation of false dangerous areas of microbursts has not been studied. This article presents mathematical relations that allow further mathematical modeling to analyze the impact of changes in the pulse duration, resolution, and level of the side lobes in the lower hemisphere in low-altitude flight conditions on the assessment of the risk of microbursts. An algorithm for processing of radar data for assessing the risk of microburst at an arbitrary pulse is presented. The results of mathematical modeling are presented. The field of microburst wind speeds at an altitude of 300 meters was set and the reflected signal processing in the radar was simulated. They prove the correctness of the estimation of the boundaries of dangerous  areas of microbursts. They also show that for flights at low altitudes, it is better to use a linear model to estimate the vertical component of wind speed during microburst. The main relations for estimating the volume of the minimum area of dangerous microburst are given, which allow us to determine the requirements for the parameters of the weather locator in order to detect this area at a given radar reflectivity. As a result, the parameters of the weather radar were determined to detect a minimally dangerous microburst area with a radar reflectivity of 20 dBz at a range of at least 12 km. In the future we plan to continue research aimed at assessing the impact of reflections from the earth's surface the probability of false detection microburst, and an estimate of about region depending on the width of the main onion, the level of lateral radiation of the antenna in the lower hemisphere and the pulse duration.

Bestugin A.R., Ryzhikov M.B., Novikova Yu.A., Kirshina I.A. Assessment of the hazard of microbursts in the onboard weather radar for small aircraft. Achievements of modern radioelectronics. 2020. V. 74. № 11. P. 23–29. DOI: 10.18127/j20700784-202011-05. [in Russian]

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