半干旱典型草原风蚀水蚀过程试验与耦合模型研究

In the semiarid regions, soil erosion is the greatest environmental, social and economic issue the world faced. In soil erosion areas, ecohydrological processes are still relatively inadequate, which leads to many ecological governance policies lack scientific basis in the implementation process. Taking a semiarid typical steppe watershed in northern China as the study area, based on available conditions in situ experiments, choose several representative aeolian and fluvial test sites across the study area. Adopt aeolian and fluvial processes experiment and simulation in point scale and synchronous measurements and monitoring weather, soil, vegetation, and topography characteristic, to obtain aeolian and fluvial erosion data and major drivers observed in situ; formulate an integrated aeolian and fluvial processes prediction model, which can simulate dynamic interactions between aeolian and fluvial erosion processes. inverse major drivers of aeolian and fluvial processes of recent thirty years, then simulate and predict aeolian and fluvial processes in regional scale; analyze monthly and yearly interactions between aeolian and fluvial erosion processes, reveal these two processes contributions to soil erosion, and the environmental conditions threshold when the key role of soil erosion was changed between aeolian and fluvial erosion processes. This project will play an important role in enriching and advancing ecohydrology subject in semiarid regions, and will provide technical information for scientifically evaluating productivity of soil erosion area as well as restoration/reconstruction and resource utilization of the fixing vegetation.

半干旱地区土壤侵蚀是当今世界面临最大的环境-社会-经济问题之一，这些区域生态水文过程基础研究相对不足，导致很多生态治理政策在实施过程中缺乏科学依据。本项目以我国北方半干旱典型草原为研究对象，在依托前期已具备的野外试验条件的基础上，在研究区设定多个具有代表性的风蚀、水蚀试验点。通过对点尺度风蚀、水蚀过程的试验模拟以及对气象、土壤、植被和地形特性的同步监测与测试，获取风蚀、水蚀及其驱动因子的原位观测数据；建立风蚀、水蚀和水文过程一体化模拟计算的风蚀水蚀耦合模型；反演近三十年来区域尺度土壤风蚀、水蚀过程的主要驱动因子，模拟预测区域尺度的风蚀、水蚀过程；分析历年和逐月风蚀、水蚀的交互关系，揭示风蚀、水蚀对土壤侵蚀的贡献率以及二者主导地位发生转换时的环境条件阈值。本研究对于丰富和完善半干旱地区生态水文学具有重要的学术价值，也可为土壤侵蚀区生产力科学评价、生态系统恢复重建与资源利用等提供技术依据。

本项目选择我国典型半干旱草原——锡林河流域为研究区，依托锡林河流域生态水文试验基地的硬件条件，开展了气象、水文、植被、土壤侵蚀等要素的野外测试。基于以上观测数据，分析了流域植被叶面积指数和生物量的变化规律，辨识了时空变异的驱动机制。基于改进遥感生态指数模型，评价了流域生态环境的健康程度。构建了流域表层土壤饱和导水率传递函数，模拟了土壤水分入渗规律。建立了土壤风蚀水蚀耦合模型，模拟了流域土壤侵蚀的动态过程。本项目执行期间，发表SCI论文2篇，累计影响因子4.300；发表中文核心期刊论文1篇，录用1篇。培养研究生5名，参加国内外学术会议9人次。本研究对于丰富和完善半干旱草原内陆河流域生态水文过程研究具有基础的学术价值，也可为天然生态系统的健康维持和退化生态系统的恢复重建提供数据支撑。