【摘要】 [目的]量化2000—2019年中国海河流域山区水沙连通性的时空变化，探究土地利用变化对水文连通性的影响，为海河山区的水沙治理提供新的依据。[方法]采用基于通用土壤流失方程植被因子（C）和植被指数（NDVI），计算两种水文连通性指数（IC），并量化年尺度下滦河流域水文连通性。[结果]（1） 2000—2019年滦县水文站控制流域内IC_c的均值分别为-1.41,-1.41,-1.41,-1.39,-1.38,IC_ndvi的均值为-2.14,-2.33,-2.56,-2.36,-2.28;IC_c和IC_ndvi的空间分布格局相似，均呈现上游<中游<下游，西北低、东南高的分布特征。（2）滦河流域IC指数变化面积占比均为不显著减少>不显著增加>显著减少>显著增加，52.39%的区域呈现不显著减少，38.67%的区域不显著增加。水文连通性减少的区域为上游西部、中游和下游东部，增加的区域主要为中下游承德、迁安等市附近。IC_ndvi指数在刻画水文连通性及其显著变化方面优于IC_c指数。（3）流域IC_c,IC_ndvi与年径流深度和年输沙模数呈现出显著的正相关关系（相关系数分别为0.6,0.7）。（4）各地类IC_ndvi均值计算结果由大到小依次为裸地0.98，建筑-0.17，农田-2.13，森林-2.54，草原-2.78，灌木-3.00，湿地-3.80，水体-3.98。[结论]随着退耕还林等工程的实施，20年间滦河水文连通性不显著减少。由农田、草原转变为森林、建筑的主要土地利用变化导致森林、农田IC_ndvi减少，草原、建筑用地IC_ndvi增加。更多还原

【Abstract】 [Objective]This study aims to quantify the spatiotemporal variations of water-sediment connectivity in the mountainous areas of the Haihe River Basin from 2000 to 2019 in China and investigate the influence of landuse variations on hydrological connectivity,providing new insights into water-sediment management in the mountainous regions of the Haihe River Basin.[Methods]Two hydrological connectivity indexes （IC） based on the vegetation factor （C） of the Universal Soil Loss Equation and the normalized difference vegetation index（NDVI） were employed to quantify hydrological connectivity at an annual scale in the Luanhe River Basin.[Results]（1） From 2000 to 2019,the mean values of IC_c in the controlled basin of the Luanxian hydrological station were-1.41,-1.41,-1.41,-1.39,-1.38,and the mean values of IC_ndvi were-2.14,-2.33,-2.56,-2.36,and-2.28.The spatial distribution patterns of IC_c and IC_ndvi were similar,both presenting upstream<midstream<downstream,with lower values in the northwest and higher values in the southeast.（2） The percentage of area with IC index changes in the Luanhe River Basin was as follows:non-significant decrease>non-significant increase>significant decrease>significant increase,with 52.39%of the area showing non-significant decrease,and 38.67%showing non-significant increase.The areas with decreasing connectivity were located in the western upstream,midstream,and eastern downstream areas,while areas with increasing connectivity were mainly in the middle and lower reaches,such as near Chengde and Qian′an.The IC_ndvi index was better than the IC_c index in depicting hydrological connectivity and its significant changes.（3） Both IC_c and IC_ndvi showed significant positive correlations with annual runoff depth and annual sediment modulus （correlation coefficients of 0.6 and 0.7,respectively）.（4） The calculated mean IC_ndvi values for different land types,from high to low,were as follows:bare land 0.98,building-0.17,farmland-2.13,forest-2.54,grassland-2.78,shrubland-3.00,wetland-3.80,water body-3.98.[Conclusion]With the implementation of projects such as Grain for Green,the hydrological connectivity of the Luanhe River Basin has not significantly decreased over the past 20 years.The major land-use changes from farmland and grassland to forests and buildings has resulted in a decrease in IC_ndvi for forests and farmland,and an increase in IC_ndvi for grasslands and buildings.更多还原