泾河流域上游景观尺度植被类型对水文过程的影响

选择具有土石山区的泾河流域上游为研究对象,应用生态水文模型SWIM对上游景观尺度下各植被类型水文效应进行了模拟,并针对上游土石山区和黄土区分海拔段进行了植被分布的水文格局影响分析。结果表明：泾河流域上游的森林、农田、草地各植被类型的蒸散及组分、径流深和土壤深层渗漏各水文过程具有显著差异,不同区域（土石山区和黄土区）的同一植被类型的各水文过程明显不同;同时,植被景观格局存在区域和海拔差异,这使得不同区域和海拔段的各水文过程有所不同。如在土石山区,以森林为主的海拔段2 250-2 922 m降水量和蒸散量均最大（分别为641 mm和484 mm）,以农田、草地和森林均有分布的海拔段1 750-2 250 m降水量较大（590 mm）,但蒸散量最低（仅为434 mm）;而在较为干旱的黄土区（降水量为514 mm）以农田和草地为主两个海拔段（1 026-1 350 m和1 350-1 750 m）的蒸散量较高（分别为458 mm和440 mm）。另外,从各水文过程要素与降水的比值看,两个区域之间差异比较明显,但同一区域不同海拔段间差异不明显。

Influence of Vegetation Type on Hydrological Process at Landscape Scale in the Upper Reaches of Jinghe Basin

Profoundly understanding the influence of vegetation types and their distribution pattern on the hydrological processes is of great significance for water resources management and vegetation reasonable recovery in a large basin scale. In this study, the upper reaches of Jinghe Basin with stony mountain area was selected as the research area, and the dynamic process-based eco-hydrological model (SWIM) was used to simulate hydrological effect of different vegetation types at landscape scale, the impact of the vegetation distribution on hydrological pattern was further analyzed by distinguishing elevation in view of stony mountain area and loess area. Results showed that hydrological effects including evapotranspiration and its components, water yield and deep soil percolation among forest, farmland and grassland had significant difference, and the same vegetation type in different regions (stony mountain area and loess area) had obviously different effects on hydrological process. Because of the area and elevation difference of vegetation landscape pattern, the hydrological process in different areas and elevation sections had difference. For example, in stony mountain area, the precipitation and evapotranspiration in elevation section of 2 250-2 922 m dominated by forest was largest to 641 mm and 484 mm respectively, while the precipitation in elevation section of 1 750-2 250 m with farmland, grassland and forest scattered around was larger to 590 mm, but the evapotranspiration was lowest to 434 mm; in arid loess area with precipitation of 514 mm, the evapotranspiration in two elevation sections of 1 026-1 350 m and 1 350-1 750 m with farmland and grassland were 458 mm and 440 mm respectively. In addition, the difference of the ratios between hydrological process elements and precipitation in both areas was more significant, but is not obvious for different elevation sections in the same area.