High-Resolution UAV Measurements of Atmospheric Boundary Layer Turbulence.

A semi-autonomous Uncrewed Aerial Vehicle (UAV) was deployed to investigate turbulence in the atmospheric boundary layer (ABL) under high Reynolds number conditions. The UAV was equipped with a five-hole probe, capable of resolving all three wind components at 100 Hz, and a hot-wire probe sampling at 50 kHz. The aircraft followed a “racetrack” trajectory aligned with the mean wind direction, allowing for spatial sampling through a moving frame of reference. Aircraft attitude (pitch, roll, yaw) and angular rates were recorded and combined with five-hole probe data to extract 3D wind velocity components. These measurements were also used to perform in-situ calibration of the hot-wire probe, enabling extension of spectral content into the inertial and dissipative subranges. The resulting dataset exhibits an inertial subrange spanning over up to six orders of magnitude in frequency, demonstrating unprecedented resolution for field-based turbulence measurements.

The mobility of the UAV platform allows for enhanced spatial sampling compared to stationary towers, while reducing reliance on Taylor’s hypothesis. However, the spatio-temporal nature of the data poses new challenges in extracting longitudinal and transverse components and validating structure function scaling in atmospheric flows. This work addresses these challenges by analyzing scaling behavior of structure function, highlighting both the promise and limitations of UAV-based turbulence diagnostics in complex, real-world environments.