To a multibeam echo sounder system (MBES), under water sound refraction plays an important role in depth measure- ment accuracy, and errors in sound velocity profile lead to inaccuracies in the measured depth (especia...To a multibeam echo sounder system (MBES), under water sound refraction plays an important role in depth measure- ment accuracy, and errors in sound velocity profile lead to inaccuracies in the measured depth (especially for outer beams). A method is developed to estimate the sound velocity profile based on the depth measured by vertical beam. Using this depth and other pa- rameters, such as t (sound pulse propagation time), θ (beam inclination angle), etc. We can estimate a simple sound velocity profile with which the depth error has been reduced. This method has been tested with a real dataset acquired in the East China Sea.展开更多
Poyang Lake in the Changjiang(Yangtze)River catchment has undergone frequent spring drought since 2003,and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel l...Poyang Lake in the Changjiang(Yangtze)River catchment has undergone frequent spring drought since 2003,and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel linking the lake with Changjiang River main channel.However,there is still a lack of high-resolution subaqueous geomorphological evidence of how sand mining led to lakebed deformation in the outlet channel.We examined the bed morphology and sub-bottom sedimentary structure of the outlet channel,using a multibeam echo sounder and sub-bottom profi ler in Poyang Lake.We found that:(1)the subaqueous micro-topography types of the outlet channel are characterized by sand mining disturbance,natural erosional topography,and fl at bed and dunes,accounting for 44.9%,21.4%,28.6%,and 5.1%of the channel area,respectively;and(2)sand mining activity aff ects the local bed topography extensively and signifi cantly.The depth of sandpits caused by sand mining varied from 1.4 m to 12 m deeper than the surrounding bed surface,with 4.41 m of depth increase on average.Hence,the large-scale high-intensity sand mining activities and their signifi cant geomorphic eff ects demand for an improved assessment for future management and longer-term sustainability.Because of the large-scale and ongoing high-intensity sand mining activities in the Poyang Lake outlet channel,these eff ects should raise caution in the future and contribute to monitoring eff orts that are essential to implement sustainable management solutions.The present study and techniques implemented can serve as a scientifi c reference for dam construction and sand mining within the Poyang Lake basin.展开更多
R2 Sonic 2022是基于第5代声呐结构的多波束测深系统,从动静态水深比测、数字地形图精度、面积法3个角度与传统回声测深仪进行对比,对比结果说明多波束测深系统具有精、准、快的特点,分析该系统在河道险工险段监测及整治、水库水下地形...R2 Sonic 2022是基于第5代声呐结构的多波束测深系统,从动静态水深比测、数字地形图精度、面积法3个角度与传统回声测深仪进行对比,对比结果说明多波束测深系统具有精、准、快的特点,分析该系统在河道险工险段监测及整治、水库水下地形测量、应急抢险,以及河道演变趋势研究中的应用,为江河湖泊的地形监测提供决策数据和技术支撑。展开更多
Shallow marine sand waves are formed on the seabed and are widely distributed within tidal environments.However,the use of multibeam echo sounding(MBES)is costly to obtain the bathymetric mapping of large complex sand...Shallow marine sand waves are formed on the seabed and are widely distributed within tidal environments.However,the use of multibeam echo sounding(MBES)is costly to obtain the bathymetric mapping of large complex sand waves.Therefore,we propose a new method that employs a combination of multiangle sun glint images and sparse MBES data to achieve comprehensive bathymetric mapping of large and complex sand waves.This method involves estimating sea surface roughness,automatically extracting sand-wave crests,conducting adaptive subregion partitioning,estimating the water depth at auxiliary points,and generating digital bathymetric models.The method was employed in a case study of sand waves on the Taiwan Bank.Bathymetric mapping was implemented for large complex sand waves over an area spanning approximately 350 km~2 using multiangle sun glint images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer and MBE S data.The results show that mapped and measured water depths were well-matched;the root-mean-square error of water depths was 1.77 m,and the relative error was 5.03%.These findings show that bathymetric mapping of large complex sand waves can be effectively conducted using the new method,and as such,the workload of MBES is reduced and efficiency is improved.展开更多
基金funded by the National High Technology Research and Development Program of China('863'Program)under contract Nos.2004AA616080 and 2006AA09ZI03the National Natural Science Foundation of China(Project code:40606026).
文摘To a multibeam echo sounder system (MBES), under water sound refraction plays an important role in depth measure- ment accuracy, and errors in sound velocity profile lead to inaccuracies in the measured depth (especially for outer beams). A method is developed to estimate the sound velocity profile based on the depth measured by vertical beam. Using this depth and other pa- rameters, such as t (sound pulse propagation time), θ (beam inclination angle), etc. We can estimate a simple sound velocity profile with which the depth error has been reduced. This method has been tested with a real dataset acquired in the East China Sea.
基金Supported by the Comprehensive survey of the geological environment along the Changjiang River(No.DD20190260)the Natural Science Foundation of Shandong Province(No.ZR2020QD083)the Postdoctoral Science Foundation(No.2018M642693)。
文摘Poyang Lake in the Changjiang(Yangtze)River catchment has undergone frequent spring drought since 2003,and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel linking the lake with Changjiang River main channel.However,there is still a lack of high-resolution subaqueous geomorphological evidence of how sand mining led to lakebed deformation in the outlet channel.We examined the bed morphology and sub-bottom sedimentary structure of the outlet channel,using a multibeam echo sounder and sub-bottom profi ler in Poyang Lake.We found that:(1)the subaqueous micro-topography types of the outlet channel are characterized by sand mining disturbance,natural erosional topography,and fl at bed and dunes,accounting for 44.9%,21.4%,28.6%,and 5.1%of the channel area,respectively;and(2)sand mining activity aff ects the local bed topography extensively and signifi cantly.The depth of sandpits caused by sand mining varied from 1.4 m to 12 m deeper than the surrounding bed surface,with 4.41 m of depth increase on average.Hence,the large-scale high-intensity sand mining activities and their signifi cant geomorphic eff ects demand for an improved assessment for future management and longer-term sustainability.Because of the large-scale and ongoing high-intensity sand mining activities in the Poyang Lake outlet channel,these eff ects should raise caution in the future and contribute to monitoring eff orts that are essential to implement sustainable management solutions.The present study and techniques implemented can serve as a scientifi c reference for dam construction and sand mining within the Poyang Lake basin.
文摘R2 Sonic 2022是基于第5代声呐结构的多波束测深系统,从动静态水深比测、数字地形图精度、面积法3个角度与传统回声测深仪进行对比,对比结果说明多波束测深系统具有精、准、快的特点,分析该系统在河道险工险段监测及整治、水库水下地形测量、应急抢险,以及河道演变趋势研究中的应用,为江河湖泊的地形监测提供决策数据和技术支撑。
基金Supported by the National Natural Science Foundation of China(Nos.41876208,41830540,41576174)。
文摘Shallow marine sand waves are formed on the seabed and are widely distributed within tidal environments.However,the use of multibeam echo sounding(MBES)is costly to obtain the bathymetric mapping of large complex sand waves.Therefore,we propose a new method that employs a combination of multiangle sun glint images and sparse MBES data to achieve comprehensive bathymetric mapping of large and complex sand waves.This method involves estimating sea surface roughness,automatically extracting sand-wave crests,conducting adaptive subregion partitioning,estimating the water depth at auxiliary points,and generating digital bathymetric models.The method was employed in a case study of sand waves on the Taiwan Bank.Bathymetric mapping was implemented for large complex sand waves over an area spanning approximately 350 km~2 using multiangle sun glint images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer and MBE S data.The results show that mapped and measured water depths were well-matched;the root-mean-square error of water depths was 1.77 m,and the relative error was 5.03%.These findings show that bathymetric mapping of large complex sand waves can be effectively conducted using the new method,and as such,the workload of MBES is reduced and efficiency is improved.
