黄土坡面细沟形态量化描述及侵蚀产沙响应规律

Morphological development of rill at slope formed a dynamic response system with soil erosion driven by rainfall. The Geomorphology embody the erosion factors and their interactions，it is the key part of the runoff process based erosion model. This study intends to take rill evolution as the starting point, the study includes tempo-spatial evolution of rill, quantization parameters of rill morphology evaluation, quantitative description of rill evolution from status and time, establish the relation between rainfall ~ erosion ~ morphological development of rill. This study was designed to overcome the problem of spatial variability on slope , which the existing erosion models failed to solve. The purpose of this study was to through the scientific quantification of rill morphology to reveal the response mechanism of rill evolution and erosion process. Using nonlinear science, topology and entropy theory quantification the slope morpholog to reflect it’s complexity and erosion, construct the quantification system of rill morphology, form a more complete system for rill morphology parameters evaluation. The purpose is through morphological development to analysis the rainfall-erosion mechanism, and provide a scientific basis for improving the reliability and accuracy of soil erosion prediction model.

坡面细沟形态是一个降雨驱动下侵蚀产沙的微地貌动态响应系统，这一地貌因素体现着坡面侵蚀动力学各要素及其相互作用，是基于物理过程的水蚀预报模型的关键部分。课题拟以细沟形态变化为切入点，研究坡面细沟时空演变规律、形态量化参数评价、“状态～时间”演化过程定量描述、坡面降雨～产沙～细沟形态定量响应规律。研究旨在克服现有水蚀预报模型中未能解决的坡面空间变异性问题，通过对细沟形态的科学量化达到揭示坡面降雨侵蚀产沙过程响应机制的目的。综合运用非线性科学、拓扑学、熵等理论建立体现坡面地貌形态信息和侵蚀信息的描述方法，形成较完整的细沟形态量化参数评价体系，从细沟形态的角度阐明坡面降雨侵蚀产沙机制，为提高水土流失预报模型的可靠性和准确性提供科学依据。

细沟形态变化直接影响坡面水文过程，进而与产汇流、产输沙形成互馈作用。这一过程体现着坡面水蚀动力学各要素对比关系，是深入认识流域侵蚀产沙物理过程的关键科学问题。项目围绕细沟形态演变过程及其对坡面水沙过程的影响，以细沟形态为切入点，将降雨-径流-地形演变-产流产沙作为一个水动力耦合系统，研究细沟形态特征量化及实现方法，揭示细沟形态演变时空分异规律，阐明降雨-产流产沙-细沟形态定量响应规律，构建体现细沟形态对侵蚀过程影响的陡坡面土壤侵蚀预报模型，研究旨在突破现有坡面水蚀预报模型中尚未解决的空间变异性问题，为水土流失过程的预测预报提供科学依据。通过 21 场坡面水蚀精细模拟降雨试验，采集到 147 组坡面 DEM 数据和 135 组降雨水沙数据，取得主要成果如下：.1、形成了集“坡面水蚀过程精细模拟-坡面微地貌DEM获取-多维形态参数提取方法”为一体的细沟形态获取及参数提取方法。.2、研究了坡面水沙过程及流速分布与细沟形态间的互馈关系，运用灰色系统理论，对形态参数间的关联度进行了分析，对各形态参数的敏感性进行了评价。.3、采用“能量+结构”的量化模式，构建了细沟形态综合量化参数，并基于综合形态量化参数的变化特征，定量揭示了细沟形态的非线性变化规律。.4、将细沟形态发育与土壤侵蚀方程相耦合，对陡坡地土壤流失预报模型进行了修正，修正后的模型精度明显提高。