黄河中游多沙粗沙区流域产沙空间分布及其演变

Studies on spatial pattern have formed a focal topic in geography. Studies on the spatial pattern of basin sediment yield have not received much attention they deserved. Most studies addressed spatial heterogeneity, yet neglecting possible spatial homogeneity. Preliminary studies have suggested a considerable spatial uniformity in basin sediment yield in the middle Yellow River. Moreover, spatial statistic analyses, which have been well applied in geography and other geoscience disciplines, are rarely used to examine the spatial pattern of basin sediment yield. In addition, among numerous studies concerning sediment dynamic in the middle Yellow River, few of them have examined the sediment dynamic in terms of spatial pattern. This project selects the coarse and high-intensity sediment-producing areas (CHIDP areas), the major sediment source area and particularly the major coarse-sediment source area of the Yellow River, as the study area. We first individually examine the spatial pattern of basin sediment yield in various land-management sub-periods, and then examine the temporal variation of the spatial pattern of basin sediment yield and determine the driving factors during the period 1950s-2010s. The project, using both technologies of classic statistics and spatial statistics, shall not only examine the spatial heterogeneity but also the spatial homogeneity of basin sediment yield. The project promises to lend scientific support to soil and water conservation and soil loss predictions in CHIDP areas.

空间分异规律是地理学重要研究内容，流域产沙空间分布研究目前还未受到应有的重视。大量研究聚焦于空间异质性分析，对空间均质性现象关注较少，而初步研究表明在黄河中游，流域产沙存有很好的空间均质性；空间统计学方法在流域产沙空间分布研究中也还未有广泛应用；此外，从空间分布的角度对黄河中游水沙变化的研究也较为缺乏。针对这些问题，本项目以黄河中游多沙粗沙区为研究区，首先分析1950s–2010s期间不同治理阶段流域产沙空间分布特性及其主控因子，在此基础上揭示流域产沙空间分布特性的演变规律及其驱动因素。项目采用空间统计并结合常规统计分析技术，不仅进行空间异质性分析，也进行空间均质性研究。本项目以揭示多沙粗沙区流域产沙空间分布规律及演变为科学目标，为该区域水土流失防治和侵蚀产沙预报提供依据。

流域产沙空间分布的研究目前还较少。本项目从空间分布的角度开展黄河中游多沙粗沙区的水沙过程研究，不仅分析流域产沙的空间变异性，也分析流域产沙的空间均质性。研究结果表明，在黄河中游支流尺度上，降雨是流域产沙空间分布的主控因子，由于降雨的空间变异随时间尺度变大而变小，故在多年时间尺度，流域产沙表现出很好的空间均质性；在河龙区间尺度，植被成为流域产沙空间分布的主控因子，致使流域产沙表现出很好的纬度变异特征，但变异并不大，仍在相当程度上表现出空间均质性。和产沙一样，产流量也存有较好的空间均质性。对小流域，产沙和产流的这种空间均质性存在于从事件到多年各个时间尺度，而对大流域，则只存在于多年时间尺度。1970年以后黄河中游开展的大规模水土流失治理，不仅显著减少了流域产流和产沙，也显著破坏了其空间均质性。项目还研发了基于线积分的贡献分解技术，提出了基于水沙关系框架的黄土流域减沙贡献分割新方法。本项目执行期间，较好地完成了项目目标，共计发表论文9篇，包括3篇SCI收录论文和1篇EI收录论文，3篇SCI收录论文均发表于中科院1区期刊上。