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黄土丘陵沟壑区大空间尺度植被减沙方程是分析黄土高原植被变化产沙效应的有效工具,其在不同空间尺度的适应性对于黄河水沙情势变化研究十分重要。运用数值试验方法,研究黄土丘陵沟壑区大空间尺度林草植被减沙方程在小流域、子流域和栅格等3种空间尺度的适应性。结果显示,黄土丘陵沟壑区大空间尺度林草植被减沙方程在各空间尺度的总体估算偏差(D)由小到大排序为小流域(D=52.26%)<子流域(D=60.07%)<栅格(D=92.17%),纳什效率系数(NSE)由大到小排序为小流域(0.21)>子流域(-0.31)>栅格(-0.80)。可见,黄土丘陵沟壑区大空间尺度植被减沙方程在约500 km2以上的流域单元较为适用,在500 km2以下的子流域和栅格单元不适用。该研究成果可为黄土丘陵沟壑区大空间尺度林草植被减沙方程的推广应用提供参考。
The large-scale spatial-scale sediment reduction equation in the loess hilly and gully regions is an effective tool for analyzing the effects of changes in vegetation and sediment yield on the Loess Plateau. Its adaptability at different spatial scales is very important for the research on the changes of water and sediment in the Yellow River. Numerical experiments were conducted to study the adaptability of large-scale forest-grassland sediment reduction equations in the hilly and gully regions of the Loess Plateau to three spatial scales: small watersheds, sub-basins and grids. The results showed that the overall estimation deviation (D) of the sediment reduction equation of large-scale forest-grassland vegetation in the hilly and gully regions of the Loess Plateau was small (D = 52.26%) subbasin (-0.31)> grid (-0.80). It can be seen that watershed units with large-scale spatial-scale sediment reduction in the loess hilly-gully area are more than 500 km2 and are not suitable for sub-basins and grid units below 500 km2. The results of this study can provide reference for the popularization and application of the large-scale spatial-scale forest-grassland sediment reduction equation in the hilly and gully regions of the Loess Plateau.