Quantitative indicator analysis of spatiotemporal riverbed coarsening in the lower Yellow River
At present,the judgment of riverbed coarsening is mostly qualitative and lacks quantitative indicators.Based on the annual average median size of bed materials at 7 major hydrological stations in the lower Yellow River from 1963 to 2020,the stream wise and temporal coarsening degrees are proposed as the quantitative indicators,the relationship between the two coarsening degrees is established,and the spatiotemporal variation of median size is revealed quantitatively.It is found that the frequency of mild coarsening is the highest and the severe coarsening is the lowest in the lower Yellow River.The average coarsening degree along the river and the average coarsening degree over time are relatively stable,both are around 1.1.There is a weak negative and weak positive correlation between the streamwise and temporal coarsening degrees at the upper stations and the lower stations,respectively.the fluctuation intensity of median size in spatial gradually increases with time,while the fluctuation intensity in temporal decreases along the river course,the spatial variation of median particle size is generally greater than that in temporal variation,and the influence of spatial position decreases along the river course,while the influence of time is generally stable.
the lower Yellow Rivermedian size of bed materialsstreamwise coarsening degreetemporal coarsening degree
万方数据
维普
