The effect of wind speed averaging time on the study of soil wind erosion on typical land surfaces

Wind erosion studies based on wind speed of different averaging times always weaken the effect of effective wind force and wind speed fluctuation, and produce large errors in wind erosion assessment. To quantitatively reveal the time scale effect of average wind speed on wind erosion research, this study analyzed the changes in wind speed distribution, as well as that in wind erosion event statistics and wind erosion amount calculation under different statistical time intervals, based on field observations. To further eliminate this time scale effect, wind speed conversion relationships of different averaging times were established through quantile matching of wind speed distribution function. The results show that as the averaging time increases: (1) both high and low wind speeds are filtered, making the proportion of medium wind speeds increasing, and wind speed distribution gets narrow significantly; (2) both the number and cumulative duration of wind erosion events decrease exponentially; (3) wind erosion amount corresponding to different wind speed grades differ significantly; (4) a continuous conversion equation between wind speed of different averaging times and that of one minute were established; (5) the time scale effect on different surface types are significantly different. In general, by using the statistical characteristics of wind speed distribution innovatively and considering difference in land surface properties, this study established an empirical wind speed conversion model on typical wind erosion surfaces, which will improve the evaluation accuracy of soil wind erosion intensity, and provide basis for the construction of process-based soil wind erosion model.