High-Resolution Estimation and Spatial Interpolation of Temperature Structure in the Atmospheric Boundary Layer Using a Small Unmanned Aircraft System

Knowledge of the effects of small-scale fluctuations in temperature on light transmission in the atmosphere is necessary for the calibration of remote sensing instruments as well as for the understanding of turbulent heat transport in the atmospheric boundary layer. Recent developments in small unmanned aircraft systems (sUAS) have allowed for direct, spatial in situ estimation of temperature in the ABL at very high temporal and spatial resolutions. Structure functions are estimated from vertical profiles of temperature collected using an ultrasonic anemometer mounted on an sUAS. Using geostatistical methodologies specifically developed for spatially non-stationary and spatially dependent random variables, we estimate temperature structure from six profiles reaching roughly 500 m in altitude A mean function is specified to account for the variation in temperature with altitude and the structure function is estimated from the residuals. A 2/3 scaling exponent is fitted to the resulting curves commensurate with the inertial subrange of turbulence. The resulting structure functions of residuals are able to resolve the inertial subrange on most profiles at a range of separation distances. We find that geostatistical methods for spatially non-stationary random variables are well suited in certain cases to describing the vertical structure of temperature in the boundary layer.