【摘要】 在黄河中游河龙区间选择了 1 6个不同自然地理类型流域 ,通过流域产沙量与降雨指标之间关系分析表明 ,不同类型流域产沙量 -降雨之间相关曲线的斜率不同 ;在相同的降雨指标条件下 ,越往北部产沙量变幅越大。流域产沙量与降雨指标之间关系的上述分异 ,主要受流域下垫面环境特性和暴雨分布特征控制更多还原

【Abstract】 Nineteen river basins in different geographical environments have been chosen to study the relations of sediment yield and rainfall in the Middle Yellow River Basin. Four major types of river basins were categorized, i.e., loess river basin with low vegetation coverage, mixed loess and rocky basin, rocky basin partly covered by loess and rocky basin. A composite index K was used as rainfall index for analysis of relations of sediment yield and rainfall. It was showed by data plotting that obvious positive relation exists between specific sediment yield and rainfall index K . The slope of line much varied from one type of river basins to another, indicating different rates at which specific sediment yield increases with the increase of rainfall index K . Moreover, obvious variation of specific sediment yield was observed for the same K value. Specific sediment yield tends to become increasingly greater from the south to the north within the studied area as index K increases. The environment features of river basins contribute a great deal to the control of the relations of specific sediment yield and rainfall index. An index VSD , integrated vegetation cover, surface material and morphological features, was used to indicate the resistance of river basin environment to erosion and relate to he specific sediment yield of river basin. It was revealed that specific sediment yield has obviously positive relations to the index VSD . It is of great interest that the places where different river basins were located on the plotting diagram are perfectly coincided with those on the diagram of the relation of specific sediment yield and rainfall K . Since rainfall index K relates to both rainstorms and the total rainfall different frequencies and intensities of rainstorms could occur for the same K value. By comparing the temporal variations of specific rainfalls with specific sediment yield, it was shown that the peaks of specific sediment yield could be produced either by one rainstorm event or by several rainstorm events, even the total volume of precipitation.更多还原