Profiling the turbulence from spectral measurements in the urban atmosphere using UAVs

The paper shows the possibility of using small UAVs with a rotary wing to monitor the state of atmospheric turbulence at different altitudes. The measurements were carried out at the Basic Experimental Observatory (BEC) of the V.E. Zuev Institute of Atmospheric Optics SB RAS. The turbulence spectra at 4, 10, and 27 m, as well as turbulence scale profiles obtained with three DJI Mavic Mini and one DJI Mavic Air quadcopters are reported. The turbulence spectra measured at different altitudes and turbulence scale profiles are compared with the data obtained from three AMK-03 automated meteorological systems installed at the 4-m and 30-m meteorological towers. It has been found that the turbulence spectra obtained with the AMK-03 and quadcopters are generally in a good agreement with some differences observed in the high-frequency spectral region nearby Hz. During the experiment, Kolmogorov turbulence was observed in the atmosphere in a wide frequency range at all altitudes. This type of turbulence was confirmed by both the AMK-03 and quadcopter data. When determining the longitudinal and lateral turbulence scales at altitudes of 4, 10, and 27 m, the least square fit method was used with the von Karman model as the regression curve. The turbulence scales calculated from AMK-03 and quadcopter data are shown to agree well. The condition describing the relation between the longitudinal and lateral scales in an isotropic atmosphere is true to sufficient accuracy.