Characterizing the spatial variations of wind velocity and turbulence intensity around a single Tamarix tree

Characterizing airflow and turbulence patterns around real vegetation is essential for predicting aeolian erosion. However, few studies have explored the airflow field around live plants. In this field study, airflow field and turbulence patterns were investigated around a single Tamarix tree. Wind speeds were monitored at 34 locations around the tree at the heights of z/h = 0.13 h, 0.5 h, 1.1 h, and 1.8 h (where h is the height of the tree) in a wind speed of 12.5 m s(-1). The results showed that a half-ellipse deceleration zone formed downwind and full-ellipse acceleration zones on the sides of the tree. The largest turbulence intensity was observed at lower heights and in the leeside of the tree where wind speed was highest, and the smallest was found on the sides where wind speed accelerated. On the sides of the tree the structure of wind speed and turbulence profiles was similar and no significant differences (P < 0.001) in wind speeds were found between identical locations. The mean wind ve-locities downwind of the tree at 0.5 h-7 h and DR1-DR4 (at the right side of the tree edge) were significantly different to the approach flow (wind speeds at-7 h) but no statistical differences were observed between wind speeds in other locations and the approach flow. The values of Rc & UDelta;x, z (wind velocity reduction coefficient) were higher in the wake of the tree than upwind and on the sides of the tree indicating that the sheltering effect of the tree extended to the distance of seven times the height tree. This study represents an important investigation of the plant effect on airflow and the results can be used to inform Tamarix management and support parameter-ization of drag partition schemes to improve the accuracy of aeolian transport models in landscapes with Tamarix.