Characterization of the atmospheric boundary layer over a tropical arid area using an airborne sonic anemometer and fixed wing UAV

Measurements within the atmospheric boundary layer are key to obtaining better understanding of the air-surface interactions and to improve models. One way to conduct this is by using uncrewed aerial vehicles with sonic anemometers, inertial navigation systems, and other instruments. This technique is explored by using an in-house experimental fixedwing UAV, with a miniature sonic anemometer, in a flat arid area found in the Sarigua National Park. Vertical profiles of wind velocity and sonic temperature were compared to ground station data and a wind profile model based on the BusingerDyer relations. The aircraft system’s averaged wind data agreed with the modeled wind profile at low altitudes, within the surface layer. However, a departure from the model was found at greater altitudes. Wind direction measured with the airborne system remained close to those measured with the ground station. Simultaneously, profiles of sonic temperature were obtained, registering a decrease with altitude during the afternoon measurements, while a morning sounding had a different shape.