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Incorporating a Rainfall Intensity Modification Factor γ into the Ia-S Relationship in the NRCS-CN Method
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  • Pengcheng Hu,
  • Jia Tang,
  • Jihui Fan,
  • Shumiao Shu,
  • Zhaoyong Hu,
  • bo zhu
Pengcheng Hu
Institute of Mountain Hazards and Environment Chinese Academy of Sciences
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Jia Tang
Institute of Mountain Hazards and Environment Chinese Academy of Sciences
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Jihui Fan
Institute of Mountain Hazards and Environment Chinese Academy of Sciences
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Shumiao Shu
Institute of Mountain Hazards and Environment Chinese Academy of Sciences
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Zhaoyong Hu
Institute of Mountain Hazards and Environment
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bo zhu
Institute of Mountain Hazards and Environment, the Chinese Academy of Sciences, Chengdu
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Abstract

Rainfall intensity is a key factor that influences the processes of infiltration and runoff generation on the surface soil. However, the Natural Resources Conservation Service runoff curve number (NRCS-CN) method, which is widely used to simulate direct runoff, does not consider the impact of rainfall intensity on the simulation results. Hence, this study incorporates a rainfall intensity modification factor (γ) into the Ia-S relationship in the NRCS-CN method. The results show that the modified method, the NRCS-CN-γ method, improves the efficiency, reduces the impact of variable rainfall intensity on the simulation results and reduces the relative errors caused by the changes in CN to approximately one-third of the original errors in the NRCS-CN method. Consequently, the NRCS-CN-γ method contributes to a more accurate simulation and prediction of direct runoff in monsoon regions where rainfall intensity greatly varies, especially under climate change.