The Planform Geometry of the Incised Mean-ders from Yibin to Yichang in the Yangtze Catchment
Many incised meanders exist in the Yangtze catchment,because their shapes are a good indication of the morphological characteristics of them and the historial information can be obtained.In this paper,the MStaT was used to get the junction angles of main rivers and tributaries,wavelet spectra,sinuosity,arc-wave-lengths,and amplitudes of incised meanders from remote sensing images,using based on wavelet analysis.Comparinged with the modern meanders,the appearances of obtuse junction angles are common,accounting for 30.3%.Near the junction points,the effects of main channel junction have a significant impact on the wavelet energy spectrum,but the wavelet energy spectrum that away from the junction point is basically un-changed.Most rivers'curvature,arc wavelength and amplitude parameters have shown a trend of gradually rising from upstream to downstream.From the analysis of valley morphology,it can also be seen that the val-ley shape of the deep river curve represented by Jialing River is mainly symmetrical valley,which indicates that the river shape has not changed on a large scale in the process of forming the deep river curve.According to the above phenomenon,we speculate that the situation where the rivers'junction angle is obtuse cannot be used as evidence of reversing the flow of the ancient Yangtze River.The Yibin to Yichang section of the Yang-tze River Basin was once a peneplain(or wide river valley)with low terrain.Incised meanders are formed by the ancient meanders in the process of deep curve.The Yangtze River should be the cause of the"superim-posed"in the Sichuan Basin and the Three Gorges regions.The flow direction of incised meanders has not been reversed on the river channels today.
the evolution of Yangtze drainage systemsincised meanderswavelet analysisSichuan BasinThree Gorges
万方数据
维普
