Characterization of atmospheric turbulence during the NATO RTG-40 land field trials

Abstract

The NATO RTG-40 Active Imaging Land Field Trials were conducted at the High Energy Laser System Test Facility at White Sands Missile Range, NM, during November of 2005. This experiment intercompared six active imager systems operating in the visible, near-infrared, and short-wave infrared sensing bands. To characterize the atmospheric turbulence structure present during the optical measurements eight scintillometers were arranged along or near the atmospheric path to characterize the vertical and temporal structure of scintillation, and inner and outer scales of turbulence. A met mast, two 32-m met towers, and an 8-m tower complemented the scintillometer data. This report focuses on analysis of data from four 3-D sonic anemometers positioned at midrange on the 8-m tower and on four of the scintillometers arranged along the 2-km propagation path. First and second order statistics from the sonic sensors are illustrated, along with an analysis of the turbulence spectrum measured by the sonic temperature sensors. The analysis of this data should support both estimating turbulence strength using sonic anemometers as well as outer scale. The data acquired throughout the 10-day measurement period and have proved useful in characterization of the overall weather conditions present during testing and in prediction of various surface layer characteristics.