A comparison of wind velocities in complex terrain between modeling and measurement in natural mesquite dune-lands in the northern Chihuahuan Desert

During the spring of 2003 and 2004, wind properties were measured above a highly-complex field of mesquite coppice dunes in the northern Chihuahuan Desert. The inter-dune areas were flat and possessed similarity in appearance to city streets; they were flat, elongated and largely oriented in the direction of the highest winds. A 15-m wind tower placed at the site measured large-scale wind properties using five anemometers, two temperature sensors, and two wind vanes. Additional wind data were obtained by eight 3-m masts placed at sites considered to be typical of different flow regions within the terrain. The masts measured wind speeds at three heights on each mast and wind direction at one height. A simulation of this site was created using QUIC version 3.5 (Quick Urban & Industrial Complex), a semi-empirical mass consistent diagnostic wind field model. Wind fields were calculated based on 10-minute averages of the wind velocity measured at the highest point on the 15-m tower at the field site. Wind velocity vectors were compared for the locations/heights obtained by the 3-m masts and were found to be similar for some situations. The comparison of the experimental wind data and the wind model were directed to the following points of interest: (1) location of shelter from the wind by the Mesquite plants; (2) locations of the highest wind velocities and wind stresses; (3) identification of the height at which the flow is above strong influence of local roughness and exhibits a mean logarithmic wind profile; (4) identification of zones downwind of mesquite bushes where there is separation flow; and (5) specification at what downwind distance from mesquite coppice dunes/ bushes plants where there is a non-separated wind profile. In addition to adding to the science of desertification and understanding of environmental degradation, the above work will possibly demonstrate a broader application for the QUIC model beyond its original targeted urban and industrial applications.