Army Research Laboratory White Sands Missile Range , NM 88002-5513 ARL-TR-4953 September 2009 Three-Dimensional Turbulence Measurements in the Atmospheric Surface Layer : Experimental Design and Initial Analysis

Abstract : The Three-Dimensional Turbulence Structure (3DTS) Test conducted in the spring of 2008 consisted of a series of measurements designed to sense three-dimensional temperature and wind turbulence structures in the near surface atmosphere. The means of performing this characterization task involved time dependent measurements taken using an array of 23 RM Young 81000 sonic anemometers. Data were sampled at 20 Hz at positions across a two-dimensional grid mounted on three towers oriented perpendicular to the expected prevailing wind. Observations were made over a 60-day period with a number of multiday sequences of continuous observations between April and June 2008. The experiment was conducted at White Sands Missile Range, NM, under dry conditions with periodic strong wind events. The dry conditions were conducive to high variations in turbulent stability conditions over diurnal cycles. Cloud coverage was minimal throughout the period. This report documents the major features of the test, including the setup, tower configuration, wind, temperature, and stability states observed, and data availability. In all, over 300 hours of complete sensor data sets were available. Stability conditions present, as characterized by the 2 m temperature gradient, ranged between -0.35 C/m during the daytime to upwards of +0.75 C/m at night, indicating significant periods of strong stable conditions.