土地利用变化及流域尺度大小对水文类型分区的影响

以海河流域为研究对象，根据1956-2005 年的年降雨量和水面蒸发资料以及DEM、土地利用和土壤的遥感资料，采用地理信息系统和多元统计分析的方法，划分一定单元流域，对海河流域进行水文类型分区划分，并讨论了土地利用转移变化及单元流域尺度大小对水文类型分区的影响。结果表明，不同土地利用情况下水文类型分区的结果是不同的，土地利用的变化会直接或间接影响流域水文类型分区的空间分布，土地利用变化越大，水文类型分区的转移变化也越大。单元流域尺度较小时，水文类型分区分布较为离散，反之，单元流域尺度较大时，水文类型分区的分布则较为连续。当单元流域平均面积变化小于150 km²时，分区分布虽然有一定的变化，但总体来看分区结果相对比较稳定，当单元流域平均面积变化较大，并达到250km²以上时，分区结果会发生较大变化。

The Impacts of Land Use Change and Watershed Scale on Hydrologic Type Regions

Using Haihe River Basin as the study area, based on the annual rainfall and water surface evaporation data of 1956-2005, digital elevation model and the remote sensing data of land use (1970, 1980, 2000) and sand content of soil, we delineate the hydrologic type regions (HTR) of the Haihe River Basin adopting GIS and multivariate statistical analyses, with the unit basin as division unit. We analyzed the average characteristic value of underlying surface conditions and climate factor in HTRs, the spatial distribution and hydrological characteristics of each region. Then the impacts of land use change and unit basin scale on hydrologic regions were discussed. Through the delineation of HTRs for Haihe River Basin based on different land use conditions, it turned out that, during 1970-1980, HTRs changed a lot that because land use varied greatly, the land use of Haihe River Basin mainly transferred from urban area and grassland to farmland, which caused HTRs transferred from HTR₂ to HTR₇ and HTR₆ to HTR₂; during 1980-2000, the land use of Haihe River Basin rarely changed, therefore HTRs varied a little. The result of hydrologic type regions varies with land use change, and land use change will directly or indirectly influence the spatial distribution of hydrologic type regions, and the more obvious the land use change, the greater the variation of hydrologic type regions. Through the delineation of HTRs for Haihe River Basin based on different unit basin scales, we found that unit basin scale plays some part in the spatial distribution discreteness of HTRs. The distribution of hydrologic regions is more discontinuous for small scale unit basins, whereas, the distribution is more continuous for large scale unit basins. Overall the delineation result is relatively stable when the change of unit basin with an average area less than 150 km², although the distribution of hydrologic type region does change, yet when a greater change of unit basin average area happens and the area variation reaches more than 250 km², the delineation result will change greatly.