Extraction of Morphometric Bedform Characteristics from Profiling Sonar Datasets Recorded in Shallow Coastal Waters of China  

作　　者：黄瀚 汪亚平 高抒 陈坚 杨旸 高建华 

机构地区：[1]School of Geographic and Oceanographic Sciences,Nanjing University [2]Third Institute of Oceanography,State Oceanic Administration

出　　处：《China Ocean Engineering》2012年第3期469-482,共14页中国海洋工程（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 40876043,40976051 andJ1103408);Public Science and Technology Research Funds Projects of Ocean (Grant No. 201105001-2);the Priority Academic Program Development of Jiangsu Higher Education Institutions fund

摘　　要：The morphological characteristics of small-scale bedforms were measured by means of an acoustic profiling sonar on the Dafeng tidal flat, Jiangsu, in 2009, and in the Jiulong Estuary, Xiamen, in 2010, respectively. The ＂multi-threshold value＂ method was utilized to reveal the morphological undulations along which bedforms were present. Analyses of the datasets obtained show that： （1） sand ripples can have irregular shapes, and （2） changes in bedform morphology are small within a single tidal cycle but may be significant over several tidal cycles. Fractal and variogram analyses of the seabed roughness revealed the existence of a significant relationship between current speed and the fractal dimension of the seabed roughness. As current speed increases, seabed roughness increases with a trend of smaller-scale bottom structures being replaced by larger-scale structures. Furthermore, the surface of the larger-scale bottom structures can either become smooth due to the absence of smaller-scale features or become rougher due to the presence of superimposed smaller-scale structures.The morphological characteristics of small-scale bedforms were measured by means of an acoustic profiling sonar on the Dafeng tidal flat, Jiangsu, in 2009, and in the Jiulong Estuary, Xiamen, in 2010, respectively. The ＂multi-threshold value＂ method was utilized to reveal the morphological undulations along which bedforms were present. Analyses of the datasets obtained show that： （1） sand ripples can have irregular shapes, and （2） changes in bedform morphology are small within a single tidal cycle but may be significant over several tidal cycles. Fractal and variogram analyses of the seabed roughness revealed the existence of a significant relationship between current speed and the fractal dimension of the seabed roughness. As current speed increases, seabed roughness increases with a trend of smaller-scale bottom structures being replaced by larger-scale structures. Furthermore, the surface of the larger-scale bottom structures can either become smooth due to the absence of smaller-scale features or become rougher due to the presence of superimposed smaller-scale structures.

关 键 词：ripple profiling sonar BEDFORM seabed roughness fractal dimension variogram method tidal flat Jiulong Estuary 

分 类 号：P737[天文地球—海洋地质]