中国水土保持科学2026，Vol.24Issue(3)：152-161,10.DOI:10.16843/j.sswc.2025302
次降雨条件下紫色土坡耕地SCS-CN模型参数优化与径流模拟
SCS-CN model parameter optimization and runoff simulation for purple soil sloping farmland under individual rainfall events
摘要
Abstract
[Objective]The purple soil hilly region,located in the upper reaches of the Yangtze River,is an important agricultural production area.However,it faces problems such as uneven rainfall distribution,frequent seasonal droughts,and prominent soil and water loss,which seriously affect the efficient utilization of water resources and the sustainable development of agriculture.Accurate simulation of rainfall-runoff is a prerequisite for the efficient utilization of rainfall resources on farmland.This study aims to optimize the SCS-CN model to improve its applicability to purple soil regions,enhance the accuracy of runoff simulation,and provide scientific support for the efficient utilization of rainfall resources and soil and water conservation.[Methods]To improve the runoff simulation accuracy of the SCS-CN model on purple soil sloping farmland,this study analyzed infiltration and rainfall-runoff characteristics based on monitoring data from standard runoff plots.A slope correction factor was introduced to modify the curve number(CN),and the initial abstraction coefficient(λ)was adjusted according to rainfall characteristics,thereby constructing an improved SCS-CN model suitable for purple soil sloping farmland.The model performance was evaluated using three indicators:Nash-Sutcliffe efficiency coefficient(NSE),root mean square error(RMSE),and percent bias(PBIAS).[Results]1)The soil infiltration rate on purple soil sloping farmland decreased with increasing slope.The infiltration rate on the 5° slope was generally higher than those on the 10° and 15° slopes.Compared with the 5° slope,the initial infiltration rates on the 10° and 15° slopes decreased by 13.75％and 50.09％,the steady infiltration rates decreased by 21.58％and 57.58％,and the average infiltration rates decreased by 23.03％and 58.99％,respectively.2)Individual rainfall events were classified into three types based on rainfall depth:Type Ⅰ(high rainfall amount,low frequency),Type Ⅱ(moderate rainfall amount,moderate frequency),and Type Ⅲ(low rainfall amount,high frequency).The runoff depth followed the order:Type Ⅰ>Type Ⅱ>Type Ⅲ.3)After applying the slope correction formula,the calibrated CNⅡ values for the 5°,10°,and 15° slopes were 78.14,78.45,and 78.77,respectively.Based on rainfall type characteristics,the optimal λ value for Type Ⅰ events with Pr>70 mm was 0.35,and for Type Ⅲ events it was 0.14.4)The simulation results of the validation set were consistent with those of the calibration set.Compared with the standard model,the slope-rainfall type correction model improved the NSE by 31％,achieved a PBIAS of 1.12％,decreased the RMSE by 33％,and yielded an R2 of 0.98.[Conclusions]The SCS-CN model incorporating both slope and rainfall type modifications exhibits the highest accuracy in simulating runoff from individual rainfall events on purple soil sloping farmland.The findings provide a scientific basis for runoff regulation and the utilization of rainfall resources during seasonal droughts in the purple soil hilly region.关键词
次降雨/坡耕地/径流模拟/SCS-CN模型/紫色丘陵区Key words
individual rainfall/sloping farmland/runoff simulation/SCS-CN model/purple hilly region分类
农业科技引用本文复制引用
陈雪,司承静,史东梅,许颖,冉文建,高家勇..次降雨条件下紫色土坡耕地SCS-CN模型参数优化与径流模拟[J].中国水土保持科学,2026,24(3):152-161,10.基金项目
国家自然科学基金长江水科学研究联合基金项目"基于水沙碳耦合调控的长江上游坡耕地水土流失防治阈值及系统治理研究"(U2340215) （U2340215）
重庆市技术创新与应用发展专项面上项目"紫色土丘陵区坡耕地坡面降雨径流资源化调控关键技术与应用"(CSTB2024TIAD-GPX0043) The Joint Fund of the National Natural Science Foundation of China and the Yangtze River Water Science Research"Study on the Threshold of Soil and Water Loss Prevention and Systematic Control of Sloping Farmland in the Upper Reaches of the Yangtze River Based on Water-Sediment-Carbon Coupling Regulation"(U2340215).The General Program of Chongqing Special Project for Technological Innovation and Application Development"Key Technologies and Application of Rainfall-Runoff Resource Utilization Regulation on Sloping Farmland in Purple Soil Hilly Regions"(CSTB2024TIAD-GPX0043). （CSTB2024TIAD-GPX0043）
