  Terahertz (THz) wireless communications have the potential to realize
ultra-high-speed and secure data transfer with miniaturized devices for
unmanned aerial vehicle (UAV) communications. Existing THz channel models for
aerial scenarios assume a homogeneous medium along the line-of-sight
propagation path. However, the atmospheric turbulence due to random airflow
leads to temporal and spatial inhomogeneity of the communication medium,
motivating analysis and modelling of the THz UAV communication channel. In this
paper, we statistically modelled the scintillation and attenuation effect of
turbulence on THz UAV channels. Specifically, the frequency- and
altitude-dependency of the refractive index structure constant, as a critical
statistical parameter characterizing the intensity of turbulence, is first
investigated. Then, the scintillation characteristic and attenuation of the THz
communications caused by atmospheric turbulence are modelled, where the
scintillation effect is modelled by a Gamma-Gamma distribution, and the
turbulence attenuation as a function of altitude and frequency is derived.
Numerical simulations on the refractive index structure constant,
scintillation, and attenuation in the THz band are presented to quantitatively
analyze the influence of turbulence for the THz UAV channels. It is discovered
that THz turbulence can lead to at most 10dB attenuation with frequency less
than 1THz and distance less than 10km.
