黔西高原地区降雨侵蚀力的简易算法

[目的]对黔西高原地区侵蚀性降雨特性进行分析并探索降雨侵蚀力的简易算法,为该区土壤侵蚀预报模型的建立提供理论依据。[方法]利用径流小区观测法,基于毕节小区2012—2014年53次降雨过程资料进行分析。[结果](1)降雨量(P)和最大60min降雨动能(E60)是影响坡面产流、产沙的两个主要因子。坡面产流、产沙与最大60min雨强(I_(60))显著相关;(2)坡面产流产沙与二元复合因子的相关系数显示,EI_(60),PI_(60)和I30I_(60)是影响坡面产流、产沙的3类主要降雨复合指标,EI30和EI_(60)与坡面产流产沙的相关系数间相差较小;(3)基于坡面产流、产沙与降雨单指标和降雨复合指标的相关关系,确定了简易算法的参数。[结论]基于可比性,以R=EI30作为参照值对3种简易算法的结果进行决定系数和偏差率比较后,得到研究区便捷、快速的降雨侵蚀力简易算法为:R=0.344(PI_(60))。

Simple Algorithm of Rainfall Erosivity in West Guizhou Plateau Area

[Objective] The characteristics of rainfall were analyzed and the simple algorithm of rainfall erosi-vity of West Guizhou plateau area were studied to provide theoretical basis for the building of the soil erosion prediction model. [Methods] 53 rainfall events of Bijie area from 2012 to 2014 were obtained by means of runoff plots observation. [Results] The results showed that: (1) rainfall amount(P) and rainfall energy of 60 minutes(E₆₀) were two important affecting factors on the processes of slope runoff and sediment. Slope runoff and sediment yield were found significantly correlated with rainfall intensity of 60 minutes(I₆₀). (2) The correlation coefficients between runoff/sediment and the mixed factors of rainfall indicated that EI₆₀, PI₆₀ and I₃₀ I₆₀ were three kinds of the most important impacting factors on soil erosion process. What is more, the correlation coefficient between runoff/sediment and EI₆₀ was slightly different with the one between runoff/sediment and EI₃₀. (3) Parameters of simple algorithm of rainfall erosivity were determined based on the above analyses. [Conclusion] Through the comparison of determination coefficients and the average error rates obtained from three algorithms, the simple algorithm of rainfall erosivity of the study area was expressed as R=0.344(PI₆₀) with reference to R=EI₃₀ for its comparability.