Opportunities to monitor the urban atmospheric turbulence using unmanned aerial system

The problem of ideal hover of an unmanned aerial vehicle in a turbulent atmosphere is considered, and the equations for estimation of turbulent fluctuations of the longitudinal and transverse components of horizontal winds are derived independently of the unmanned aerial vehicle orientation and wind direction. Experiments were carried out on the territory of the Geophysical observatory of Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch, Russian Academy of Sciences. It is situated in Tomsk Akademgorodok, on the territory with complex orography, in a parkland zone with buildings of research institutes and motorways. A DJI Phantom 4 Pro unmanned aerial vehicle flew up to an altitude of 30.7 m and approached an automated weather station, mounted at a mast near the Observatory. Time series of turbulent fluctuations of the longitudinal and transverse components of the horizontal wind were received with the use of the automated weather station, and time series of turbulent fluctuations of estimates of these components, from data of unmanned aerial vehicle in the hovering mode. According to the automated weather station, anisotropic fluctuations of the turbulent flow velocity were observed during the atmospheric measurements: the spectra of fluctuations of the horizontal components coincide, but differ from the spectrum of vertical fluctuations. The spectra of fluctuations of the longitudinal and transverse components of the horizontal wind velocity were comparatively analyzed. The general coincidence of these spectra with the spectra of fluctuations of estimates of the components is shown, with, however, significant differences in the high-frequency spectral region.