Rainfall intensity and antecedent soil moisture are key variables affecting the initiation and accumulation of runoff, and therefore, impact on the occurence flood events. We used time series of rainfall intensities characterizing rainstorms with different mean, standard deviation, and skewness to simulate runoff response of a sealed loamy soil profile under various initial soil moisture conditions. We found that shifting from wet to dry initial soil moisture leads to a 300 % increase in ponding time and a 350 % decrease in total runoff. Intense rainfall events catalyze runoff development and runoff occurs earlier with increasing mean, maximum intensity, and variance of rainfall. Higher variance in intra-event storm-intensity temporal distribution yields more runoff. Earlier runoff formation aligned with negatively skewed storm structures, but largest cumulative runoff resulted from storms displaying near-zero skewness values. The combination between rainfall intensification and extended dry periods between storms might reduce potential runoff. These insights improve our understanding of anticipated impacts of climate variations on floods and may also contribute to ecosystem health evaluations, and bolster predictive capabilities of surface processes.

中文翻译：

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半干旱环境中径流的产生：暴雨事件内时间变化和前期土壤湿度的作用


降雨强度和前期土壤湿度是影响径流发生和积累的关键变量，从而影响洪水事件的发生。我们使用具有不同平均值、标准差和偏度的表征暴雨的降雨强度时间序列来模拟密封壤质土壤剖面在各种初始土壤湿度条件下的径流响应。我们发现，初始土壤湿度从湿润转变为干燥会导致积水时间增加 300%，总径流减少 350%。强降雨事件会促进径流发展，并且随着降雨的平均值、最大强度和方差的增加，径流发生得更早。事件内风暴强度时间分布的较高方差会产生更多径流。早期径流形成与负偏斜风暴结构一致，但最大的累积径流是由显示接近零偏斜值的风暴产生的。降雨强度加大和暴风雨之间干旱期延长可能会减少潜在径流。这些见解提高了我们对气候变化对洪水的预期影响的理解，也可能有助于生态系统健康评估，并增强地表过程的预测能力。