Threshold wind velocities for sand movement in the Mescalero Sands of southeastern New Mexico

摘要

Saltation activity and threshold velocities were measured at two Chihuahuan Desert sites located in the Mescalero Sands to the east of Carlsbad, New Mexico. Sand movement was detected with piezoelectric saltation sensors, and these data were used to calculate saltation activity and threshold wind speeds for the two sites. Significant blowing events were observed on nine days of this 112-day study, and it was only during these active periods that threshold values could be calculated. During periods of sand transport, threshold values were calculated every 5 min. Average threshold values typically exceeded 10.5 m/s at both sites; these are about twice those measured previously at a less vegetated dune site in West Texas. Less saltation activity occurred at the Gnome site compared with the Near Field site, especially during April; and while this can be partially attributed to differences in wind speed, additional studies are needed to evaluate other important factors such as the influence of undulating terrain and complex vegetation. Nevertheless, the results demonstrate the feasibility of long-term unattended monitoring of wind erosion activity in remote locations and that reliable and consistent estimates of threshold velocity can be obtained in complex desert environments using the time-fraction-equivalence principle.