Abstract Zhang et al. (2019) reported results from experiments where 80 cm long clayey lossal soil surfaces eroded by rain-impacted flow produced by artificial rainfalls. The target was surrounded by a 30 cm buffer area and slots along the sides of the target enabled splashed material to be collected during the experiments that lasted about 40 mins. Both splashed material and material discharged by the rain-impacted flow were collected in order to produce data on splash and sediment discharge rates for each rainfall event. Slope gradients ranging from 7 ° to 25 ° and rainfall intensities varying from 42 mm hr−1 to 90 mm hr−1 were used in the experiments. Splash rates initially decreased rapidly before reaching relatively steady values. Sediment discharge rates for 90 mm hr−1 rainfalls showed a similar pattern. However, with 42 mm hr−1 and 60 mm hr−1 rainfalls, there was an initial increase in sediment discharge rate followed by a peak before sediment discharges declined towards steady values which were not achieved with 42 mm hr−1 rainfalls. Given current understanding of sediment transport in flows deeper than 1–2 mm, it is suggested here that particles of different sizes and densities travel at different rates in the very shallow flows that operated in these experiment and, because the steady state discharge is not achieved until the slowest moving particle detached at the top of the slope is discharged, that the effects of slope gradient, rainfall intensity and time on the sediment discharge rates observed result from the numerous time scales that operate to transport eroded material over the surface. Also, because results using other soils in the same apparatus by others show temporal variations in sediment discharges that differ between different soils, it is suggested that additional work is required beyond experiments such as those reported by Zhang et al. (2019) before the processes that operate in very shallow flows are well understood.

中文翻译：

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评“粘土质黄土层间冲刷及侵蚀限制程度雨滴脱离样地试验研究”

摘要张等。(2019) 报告了实验结果，其中 80 厘米长的粘土质流失土壤表面被人工降雨产生的雨水影响流侵蚀。目标被一个 30 厘米的缓冲区包围，沿着目标两侧的槽使得在持续约 40 分钟的实验期间能够收集飞溅的材料。收集飞溅的物质和受雨水影响的水流排放的物质，以生成每次降雨事件的飞溅和沉积物排放率数据。实验中使用了范围从 7° 到 25° 的坡度梯度和范围从 42 mm hr-1 到 90 mm hr-1 的降雨强度。在达到相对稳定的值之前，飞溅率最初迅速下降。90 mm hr-1 降雨的沉积物排放率显示出类似的模式。然而，对于 42 mm hr-1 和 60 mm hr-1 降雨，沉积物排放速率最初增加，然后在沉积物排放下降到稳定值之前达到峰值，这是 42 mm hr-1 降雨无法实现的。鉴于目前对深度超过 1-2 毫米的水流中沉积物输送的理解，这里建议不同大小和密度的颗粒在这些实验中操作的非常浅的水流中以不同的速率行进，因为没有达到稳态排放直到在斜坡顶部分离的最慢的移动颗粒被排放，斜坡梯度、降雨强度和时间对观察到的沉积物排放率的影响是由许多时间尺度造成的，这些时间尺度用于在地表运输侵蚀物质。还，由于其他人在同一设备中使用其他土壤的结果显示不同土壤之间沉积物排放的时间变化不同，因此建议在实验之外需要额外的工作，例如 Zhang 等人报告的那些。（2019）之前，在非常浅的流动中运行的过程被很好地理解。