| 2 | 水利工程对长江荆南三口水系结构变化的影响显示文摘利用1954、1975、1990、2008和2016年5期长江荆南三口水系图进行解译,并运用灰色关联度模型定量评价区内外水利工程对水系结构变化的影响。结果表明:①近60多年来,荆南三口在水系结构一般特征上,河流数量由264条缩减为132条,河流长度由2183.6km缩短为1560.6km,河频率与水面率分别由0.084条/km2、17.45%减小为0.042条/km2、14.33%;在水系结构发育特征上,河网密度、面积长度比和河网发育系数由1954年的0.687km/km^2、3.96km/km^2、6.902,依次减小为2016年的0.475km/km^2、3.17km/km^2、4.165;从分形特征上看,三口水系4个河区的分维数都在1.5~2.0之间波动,但均呈下降趋势。这表明随着水利工程的不断建设,荆南三口水系自然发育过程受到严重干扰;②水系结构特征变化受水库总库容影响最大,内部水利工程次之,外部水利工程影响最小,各项指标的灰色关联度均大于0.5。其中,区外水利工程与河频率、水面率、河网密度、河网发育系数、分形维数的灰色关联度分别为0.5718、0.5922、0.5858、0.5771、0.6340;区内水利工程数量与各项指标的灰色关联度分别为0.6325、0.6527、0.6465、0.6306、0.6937;水库总库容与各项指标的灰色关联度依次为0.7070、0.7294、0.7226、0.7127和0.7284。③水利工程对水系结构的影响在不同时段呈现出不同的状态,在不同时期水利工程相继运行的叠加影响下,水系受到水利工程影响逐渐增大,水系结构逐步呈现简化趋势。 | 李景保 何蒙 于丹丹 杨波 | 2019 | 地理科学2019，39，6： | 8 |
| 3 | Multifractal features of the particle-size distribution of suspended sediment in the Three Gorges Reservoir, China显示文摘The Three Gorges Reservoir(TGR)in China is the largest hydroelectric project in the world,but the threat of sediment affecting ecological sustainability of the reservoir is a topic of concern.Sediment particlesize distribution(PSD)is informative in understanding sediment transport dynamics and biochemical functions.It is,therefore,important to quantitatively characterize the distribution of sediment particles.In the current study,fractal theory is applied to determine the PSD of suspended sediment in the TGR.The results show that the volumetric fractal dimension(D_v)exhibits a significant seasonal difference(p<0.05),reflecting sediment source and hydrodynamic sorting control the granularity of suspended sediment in the TGR.More specifically,suspended sediment particles are coarser in the wet season than in the dry season for the Yangtze River,and the opposite is true for the Ruxi River,an important tributary.The generalized dimension spectrum,D(q)-q,and multifractal singularity spectrum,f[α(q)]-α(q),were calculated for each suspended sediment sample.Thereafter,the parameters,D(0),D(1),D(2),α(0),Δα(q),andΔf[α(q)],were determined to characterize the PSD.As a result,the coarser suspended sediment during the wet season is characterised by a more complex PSD pattern,with a wider range of particle sizes,greater heterogeneity,and greater homogeneity of distribution over the measurement interval.However,the multifractal structure of the PSD of suspended sediment is more complex during the dry season than during the wet season,with higher local dispersion and variability.The findings of the current study highlight that multifractal analysis provides important insight for understanding the PSD of suspended sediment in the TGR. | Jinlin Li Xiubin He Jie Wei Yuhai Bao Qiang Tang Jean de Dieu Nambajimana Gratien Nsabimana Dil Khurram | 2021 | International Journal of Sediment Research2021，36，4： | 0 |
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