The sensitivity of infiltration predictions by Hydrus-1D and Green-Ampt models to rainfall discretisation was investigated by assessing the accuracy of infiltration predictions with rainfall rate profiles at step sizes D between 2 and 1440 min. Five peak rainfall profiles and one sine-wave rainfall profile, all with a cumulative rainfall amount of 28.8 cm and a duration of 24 h were used. Discrete rainfall profiles were generated based on the peak rainfall profiles for several step sizes. The rainfall profiles were evaluated in a sandy loam with a high saturated hydraulic conductivity and a silt loam with a low saturated hydraulic conductivity for two initial pressure heads. For both models, insensitivity was found below a critical step size D_crit, whereas high sensitivity was observed above it, D_crit depending on soil hydraulic conductivity and rainfall peak intensity, regardless of initial pressure head. In the sandy loam, D_crit was 20–30 (high-intensity peak) and 70 min (low-intensity peak); in the silt loam, values were 100 and 200–300 min, respectively. Therefore, rainfall data from common weather station data at D = 60 min allow accurate estimates of infiltration only in low-conductivity soils or for low-intensity rainfall. The disaggregation of daily cumulative rainfall into sine-wave profiles improved predictions in more conductive soils. Results indicate that higher saturated hydraulic conductivity and intensity peak rainfall rate require smaller values of D for the accurate modelling of infiltration with Hydrus-1D and Green-Ampt models.

中文翻译：

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入渗建模对降雨数据时间分辨率的敏感性

Hydrus-1D 和 Green-Ampt 模型的入渗预测对降雨离散化的敏感性通过评估降雨率分布在2 到 1440 分钟之间的步长D的入渗预测的准确性进行了研究。使用了 5 个峰值降雨剖面和 1 个正弦波降雨剖面，累积降雨量均为 28.8 cm，持续时间为 24 h。根据几个步长的峰值降雨剖面生成离散降雨剖面。在具有高饱和导水率的砂壤土和具有低饱和导水率的粉砂壤土中对两个初始压头的降雨剖面进行了评估。对于这两种模型，在关键步长D _{crit以下发现不敏感}，而在其上方观察到高灵敏度，而D _crit取决于土壤水力传导率和降雨峰值强度，而与初始压力水头无关。在砂壤土中，D _crit为 20-30（高强度峰值）和 70 min（低强度峰值）；在粉砂壤土中，值分别为 100 和 200-300 分钟。因此，来自D = 60 分钟的普通气象站数据的降雨数据 仅允许准确估计低电导率土壤或低强度降雨的入渗。将每日累积降雨分解为正弦波剖面改进了对导电性更强的土壤的预测。结果表明，较高的饱和导水率和强度峰值降雨率需要较小的值D用于使用 Hydrus-1D 和 Green-Ampt 模型进行准确的渗透建模。