Acoustic multibeam system for 3-dimensional bedform evolution studies

用于 3 维床形演化研究的声学多波束系统

基本信息

批准号：
345318-2007
负责人：
Hay, Alexander
金额：
$ 3.87万
依托单位：
Dalhousie University
依托单位国家：
加拿大
项目类别：
Research Tools and Instruments - Category 1 (<$150,000)
财政年份：
2007
资助国家：
加拿大
起止时间：
2007-01-01 至 2008-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=364753
关键词：
Acoustic multibeam system dimensional bedform

项目摘要

The equipment requested is a high-frequency acoustic multibeam system for obtaining high-resolution profiles of the seafloor at frame rates approaching that of video systems. The bed elevation profile is obtained by steering the acoustic beam spot electronically over the seafloor. Based on an earlier design operating at an acoustic frequency of 260 kHz (6-mm wavelength), this newly-developed Canadian-built sensor operates at 2.25 MHz (0.7-mm wavelength), the shorter wavelength providing much higher spatial resolution. To obtain a 3-dimensional map, the acoustic sensor must be mechanically driven in a direction orthogonal to the beam-steering plane, and thus funds are also requested to purchase a rotator unit for this purpose. The combined multibeam/rotator system will be capable of generating 3-d maps of the small-scale seafloor topography over a 5-m by 5-m area with a horizontal resolution of a few cm or better, and better than 1-cm vertical resolution, in tens of seconds. Given the 10-s typical periods of wind-generated sea-and-swell waves, this acquisition time is commensurate with the passage of several surface gravity waves. Thus, the system will enable first-time investigations of the evolution of mobile seafloor topography on the time scales of wave-groups. The system will be deployed in the fall of 2007 for 2 months as part of an investigation of the temporal evolution of wave-formed ripples on inner shelf in coarse- and fine-grained sands.

所请求的设备是一种高频声学多冰系统，用于以接近视频系统的框架速率获得海底的高分辨率轮廓。通过以电子方式在海底上转向声学束点，可以获得床的高程轮廓。基于以260 kHz（6毫米波长）的声学频率运行的较早设计，该新开发的加拿大构建的传感器以2.25 MHz（0.7毫米波长）运行，该波长较短，可提供更高的空间分辨率。为了获得3维图，必须将声传感器机械地朝向梁驱动平面的方向驱动，因此还要求资金为此目的购买旋转器单元。组合的多束/旋转器系统将能够在5米乘5 m的面积上生成3-D地图的3-D地图，水平分辨率为几厘米或更好，并且比1 cm垂直分辨率更好，以数十秒钟的速度分辨率。鉴于有10 s的风产生海水波的典型时期，此采集时间与几个表面重力波的通过相称。这是该系统将在波动组的时间尺度上进行移动海底地形发展的首次投资。该系统将在2007年秋天部署2个月，这是对内架子粗砂和细粒砂暂时进化的投资的一部分。