Submitted to: Geomorphology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2003
Publication Date: 11/4/2004
Citation: Erpul, G., Norton, L.D., Gabriels, D. 2004. Splash-saltation trajectories of soil particles under wind-driven rain. Geomorphology. 59(2004):31-42.
Technical Abstract: It is usually recognized that relatively large amounts of soil particles cannot be transported by raindrop splashes under windless rain. In wind-driven rains, however, variations in splash-saltation trajectory due to the wind as a factor capable of transporting splashed soil particles by raindrop impact are expected, and the splash-saltation process can cause net transportation in the prevailing wind direction. Therefore, a determination of the combined effect of rain and wind on the process gives a great chance to a given prediction technology to improve the estimation of erosion. This paper presents experimental data on the effects of slope aspect, slope gradient, and horizontal wind velocity on the splash-saltation trajectories of soil particles under wind-driven rains. In a wind tunnel facility equipped with a rainfall simulator, the rains driven by horizontal wind velocities of 6, 10, and 14 ms-1 were applied to three agricultural soils packed into 20 by 55 cm soil pan placed at both windward and leeward slopes of 7, 15, and 20%. Splash-saltation trajectory was measured by trapping the splashed particles at distances on a 7-m uniform slope segment in the upslope and downslope directions, respectively, for windward and leeward slopes. Exponential decay curves were fitted for the mass distribution of splash-saltation sediment as a function of travel distance, and the average splash-saltation trajectory was derived from the average value of the fitted functions. The results demonstrated that the average trajectory of a raindrop-induced and wind-driven soil particle was significantly affected by the wind shear velocity, and it had the greatest correlation (r = 0.96 for all data) with the shear velocity; however, neither slope aspect nor slope gradient significantly predicted the splash-saltation trajectory.