In this study, an assessment of similarity relationships across runoff measurements at various spatial scales was carried in a typical Sahelian landscape, under semi-arid climate in northern Burkina Faso (west African Sahel). The scales of observations considered are the plot scale (1 m², 50 m², 150 m²) and the sub-catchment scale (6.1 ha, 33.8 ha), with various soil surface conditions and slopes. These scales were monitored during six years (2010–2015) under natural rainfall. Based on monitoring data, a runoff potential index I₁ and an effective runoff index I₂ are developed, encapsulating the physical characteristics of the observation scale into dimensionless forms, hence reducing their sensitivity to the scale effects. These indices help in assessing hydrological similarity across measurement scales. Results showed that runoff decreases with the increase of the observation scale size. Besides, dimensionless indices vary following a logarithmic decay relationship with the scale size (R² > 0.98). Such results highlight the non-linear nature of runoff processes and also promotes similarity analysis as a means to model hydrological processes through soil surface conditions and landscape descriptors.

在这项研究中，在布基纳法索北部（西非萨赫勒）半干旱气候下的典型萨赫勒景观中，对不同空间尺度上径流测量的相似关系进行了评估。所考虑的观测尺度是样地尺度（1 m ²、50 m ²、150 m ²）和子流域尺度（6.1 公顷、33.8 公顷），具有各种土壤表面条件和坡度。这些尺度在自然降雨下的六年（2010-2015）期间进行了监测。根据监测数据，径流潜力指数I ₁和有效径流指数I ₂开发，将观测尺度的物理特性封装成无量纲形式，从而降低它们对尺度效应的敏感性。这些指数有助于评估跨测量尺度的水文相似性。结果表明，径流随观测尺度的增大而减小。此外，无量纲指数随着尺度大小的对数衰减关系而变化（R ²  > 0.98）。这样的结果突出了径流过程的非线性性质，也促进了相似性分析，作为通过土壤表面条件和景观描述符模拟水文过程的一种手段。