坡面是黄土高原土壤侵蚀的重要来源,本文以团山沟流域的7个径流场9年的降雨-径流事件,对不同坡面和降雨特征下径流系数随坡面的变化进行了研究。结果表明,研究区存在降雨强度大、持续时间短的A型雨、降雨强度小持续时间长的C型雨以及居于二者之间的B型雨。不同雨型下坡面产流能力大小为A型雨〉B型雨〉C型雨,而产流尺度效应则为C型雨〉B型雨〉A型雨。坡度一定,A型雨下随着坡面长度增加产流能力先增加后减小,径流系数峰值出现在坡长为40m的坡面上,B型和C型雨坡面产流能力随坡面长度的增加而增加;坡长一定,峁坡区坡面产流能力随着坡度的增加而增加;A型雨下沟坡产流能力最小,而在B型和C型雨下,坡面产流能力相对有所提高。
Slope surface is the most important sediment source area in basins on the Loess Plateau, and it is of great significance to the study on runoff generation capacity influenced by rainfall and slope surface characteristics. Seven runoff plots, located on the shady side of Tuanshangou Gully in hilly loess region on the Loess Plateau, were selected in this paper, using nine years of dataset, and the changing rule of runoff coefficients on different slope surfaces were studied in the context of different rainfall regimes. According to rainfall depth, rainfall duration, and rainfall intensity, the nine years of rainfalls in the study area were classified into three regimes through K-means clustering in SPSS software, i. e. rainfall regime A with high rainfall intensity, short duration and high occurring frequency, rainfall regime C with low rainfall intensity, long duration and low occurring frequency, and B the medium. Studies found that, for each of the study plots, runoff coefficients induced by rainfall regime A were the highest, and those induced by rainfall regime C the lowest. However, scale effect on runoff induced by rainfall regime A was the least, and that induced by rainfall regime C the largest. In slope Mao region, given the same slope degree, runoff coefficients firstly increased, and then decreased, and a peak value occurred for rainfall regime A on the slope surfaces of Nos. 2-4 plots, however, runoff coefficients increased with increasing slope lengths for rainfall regimes B and C. For the slope surfaces of Nos. 1, 4, and 5 plots that have the same slope length, under all the three rainfall regimes, runoff coefficients increased with increasing slope gradients. Entering gully slope area, runoff plot No. 6 had the lowest coefficient in the condition of rainfall regime A and those induced with rainfall regimes B and C had higher values. For entire slope surface of No. 7 plot, runoff coefficients induced by the three rainfall regimes had the medium values.