Topographic Decomposition And Reconstruction Of Sand Waves Fields On The Taiwan Banks

Sand wave is a kind of seafloor landform widely existing on tide-controlled continental shelf.Migrating sand wave is a kind of natural disaster,which endangers Marine engineering facilities.In addition,sea sand is also an important Marine resource of China,and the study of sand wave is of great value.Based on the multi-beam bathymetric data obtained from the voyage survey of Taiwan Banks,this paper proposes and implements a decomposition method for complex sand waves,and then quantitatively studies the morphological characteristics of sand waves in Taiwan Banks.Finally,based on the study of the sand wave characteristics in the study area,a method of sand wave topographic reconstruction is proposed.The main contents and results are as follows:(1)This paper conducted a statistical study on the sand wave morphological characteristics in the Taiwan Banks.It is found that there are three types of sand waves widely distributed in the Banks:bimodal,trochoidal and progressive.By improving the cycloidal equation,the section fitting functions of different types of sand waves are obtained.In addition,based on the statistical results of sand waves,the power function relationship of sand wave length and wave height is H=1.2194L0.3763,which is also an important basis for calculating wave height parameters in the sand wave topography reconstruction method.(2)A topographic decomposition method for the landform superimposed by multi-scale sand waves is proposed.Based on the principle of Fourier transform and butterworth filter,the separation and quantization of multi-scale sand waves are realized.The numerical water digital bathymetry model(DBM)of three scales of sand waves is established.(3)On the basis of studying the morphological characteristics of sand waves in Taiwan Banks,this paper proposes a sand wave topographic reconstruction method.Using the different types of sand wave profile fitting function,the sand wave depth point assignment is realized along the direction of the sand wave profile.Finally,the digital sand wave depth model is constructed by spatial interpolation.The results show that this method can realize the terrain reconstruction of sand wave well.