浅海浑浊水体环境下高时空分辨率海底地形超声观测系统

High spatial and temporal resolution seafloor topography data is very important to sedimentary dynamics, especially the benthic boundary layer. Current measurement instruments and systems can not satisfy the various studies on the evolution of the seafloor topography. According to the strong interaction between the ultrasound wave and the seafloor sediments in shallow sea environment, as well as the energy dissipation characteristics of the internal friction among the sedimentary layer particles, the seafloor sediments can be defined as a porous and viscoelastic physical model. this model reflects more realistically the effects of the seafloor sediments on ocean sound field, submarine acoustic scattering characteristics and seafloor topography detection. Ultrasound echo signal of the high spatial resolution seabed topography in the shallow water environment can be obtained through beamforming algorithm with the optimum gain and noise field characteristics, which is based on a maximum SNR criterion.The project will complete the overall design and development of high spatial and temporal resolution three-dimensional seabed terrain ultrasound observation system, which is able to output the undersea section graph ics, two-dimensional contour plots and 3D seafloor topography evolution graphics. This project will play a stimulating role on the studies of the sedimentary dynamics and sediment transport. The system can be extended to the monitoring of beaches and dunes terrain, with a wide range of social benefits.

高时空分辨率海底地形数据对于沉积动力学尤其是海底边界层研究十分重要。现有测量仪器和系统不能满足各项研究对海底地形演化信息在时空分辨率、测量精度和效率方面的要求，特别是浅海浑浊水体环境下的地形测量更存在着许多特殊之处。本项目根据浅海环境下超声波与海底沉积层存在强相互作用，以及沉积层介质颗粒间的内摩擦导致能量耗散的特性，将海底沉积层定义为多孔粘弹性物理介质模型，更真实地反映了海底沉积层对海洋声场、海底声散射特性和海底地形探测的影响；同时，基于最大信噪比准则，建立具有最佳增益与噪声场特性的波束形成算法，获取浅海环境下的高空间分辨率的海底地形超声回波信号；初步完成高时空分辨率三维海底地形超声观测系统的总体设计和研制，输出显示海底断面图形、二维等高线图和三维海底地形演化图形。本项目研究对沉积动力学和沉积物输运、以及边界层研究都将产生推动作用；该系统可推广至滩涂和沙丘等的地形监测，具有广泛的社会效益。

高时空分辨率海底地形数据对于沉积动力学尤其是海底边界层研究十分重要。现有测量仪器和系统不能满足各项研究对海底地形演化信息在时空分辨率、测量精度和效率方面的要求，特别是浅海浑浊水体环境下的地形测量更存在着许多特殊之处。本项目旨在研制高效获取浅海环境下的高空间分辨率的海底地形观测系统。本项目的研究对沉积动力学和沉积物输运、以及边界层研究都将产生推动作用；该系统可推广至滩涂等的地形监测，具有广泛的自然科学和社会经济效益。