Unmanned Aircraft Observations of Terrain Impact on the Atmospheric Boundary Layer Evolution

Three dimensional observations within the atmospheric boundary layer (ABL) are necessary to provide a better understanding of the spatio-temporal nature of the ABL structure. Previous studies have demonstrated using unmanned aerial vehicles (UAV) or umanned aircraft systems (UAS) to measure flows of interest such as the diurnal boundary layer. This talk will focus on the downstream evolution of the ABL as impacted by natural and man-made terrain, such as buildings, dunes, farmland, or waterways, to provide a unique view of the transient and spatial nature of the ABL under varying boundary conditions at the surface.

An approach is taken to measure multiple points simultaneously in the wake using highly coordinated and autonomous UAV swarms that include both thermodynamic (pressure, temperature, and humidity) and kinetic (viz., wind) probes. The swarming allows control of multiple unmanned aircraft in formation without direct pilot input and can adapt to observations autonomously to optimize the observation parameters, such as grid spacing. The ability to perform such measurements is made possible due to the integration of fast response aerodynamic probe technology with compact hardware that enables the UAV to be used in this operation. This insight provides a real time full scale measurements of the effects on the boundary layer conditions. Results are presented from studies in sand dunes and from the LAPSE-RATE¹ campaign. This environment provided a variety of interesting sampling opportunities related to boundary layer structure and development and its connection to complex terrain, convective initiation, and surface fluxes.

This research is part of CLOUD-MAP², a National Science Foundation (NSF) funded grant led by Oklahoma State University (OSU), the University of Oklahoma, the University of Kentucky, and the University of Nebraska Lincoln. CLOUD-MAP is focused on the development and implementation of unmanned aircraft systems and their integration with sensors for atmospheric measurements on Earth with and emphasis on Meteorology and Atmospheric Physics. CLOUD-MAP has objectives to create and demonstrate UAS capabilities needed to support UAS operating in the extreme conditions typical in atmospheric sensing, as well as develop and demonstrate coordinated control and collaboration between autonomous air vehicles during MAP missions.

¹Lower Atmospheric Process Studies at Elevation - a Remotely-piloted Aircraft Team Experiment

²CLOUD-MAP: Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics