Coastal and Continental Shelf Oceanography

目的：长期目标是改进对移动的海床在近岸和大陆架环境中对波流强迫的动态调整的预测。主要的短期目标是使用和开发先进的声学遥感系统，以调查在主动输送条件下底部边界层中动量和沉积物的湍流通量，以及高流量潮汐通道中湍流的极值统计。方法：（1）将在实验室和实地实验中使用内部开发的最先进、高分辨率、分辨率高的多频声学多普勒剖面系统，以远距离测量演变中的移动的海床上方的速度、湍流和沉积物通量的时空结构。(2)将在高流量潮汐通道的中层深度，使用现场快速响应湍流探测器直接调查湍流在1秒至1个月时间尺度上的变化，并使用多个先进的声学多普勒系统远程调查。(3)将使用装有仪器的机器人水面航行器研究风暴期间在近岸区和内大陆架对波流强迫的移动的河床调整，以及对沙丘和巨型沙丘的调整，以适应高流量潮汐通道中的强烈湍流和逆流条件。 ** 意义：调整移动的海底沉积物以适应流体强迫变化是现代海洋科学的重要挑战之一。其重要性在于：（A）应用科学和社会需要更准确地预测传统上与海岸线和沿海基础设施保护有关的海底变化，现在包括海底稳定性对可能开发高流量潮汐通道的影响，以便利用流中涡轮机进行可再生水力发电;（B）湍流和海底调整对沿海和整个大陆架环境条件的可预测性的影响，（C）通过沉积记录改进古环境条件解释的潜力。挑战在于：（1）观测困难，（2）移动的沉积物的响应和上覆流体的运动是相互的和非线性的，（3）与流体湍流的基本联系，经典物理学中未解决的重大问题之一。**

OBJECTIVES: The long-term goal is improved predictions for the dynamic adjustment of mobile beds to combined wave-current forcing in nearshore and continental shelf environments. The primary short term goal is to pursue the use and development of advanced acoustic remote sensing systems for investigating the turbulent fluxes of momentum and sediment in the bottom boundary layer under active transport conditions, and the extreme value statistics of turbulence in high-flow tidal channels.******APPROACH: (1) A state-of-the art, high-resolution, turbulence-resolving, multi-frequency acoustic Doppler profiling system developed in-house will be used in laboratory and field experiments to remotely measure the space-time structure of velocity, turbulence and sediment flux above evolving mobile beds. (2) The variability of turbulence on 1-second to 1-month time scales will be investigated at mid-depth in high-flow tidal channels both directly, using in situ fast-response turbulence probes, and remotely, using multiple advanced acoustic Doppler systems. (3) Mobile bed adjustment to wave-current forcing in the nearshore zone and inner continental shelf during storms, and adjustment of dunes and mega-dunes to the intense turbulence and reversing current conditions in high-flow tidal channels, will be investigated using an instrumented robotic surface vehicle. ******SIGNIFICANCE: The adjustment of mobile seabed sediments to fluid forcing variability is one of the important challenges in modern ocean science. The importance resides in: (A) the applied science and societal needs for more accurate predictions of seabed change related to shoreline and coastal infrastructure protection traditionally, and now including the effects of seabed stability on the potential development of high-flow tidal channels for renewable hydroelectric power generation using in-stream turbines; (B) the effects of turbulence and seabed adjustment on the predictability of coastal and shelf-wide environmental conditions, and (C) in the potential for improved interpretation of paleo-environmental conditions through the sedimentary record. The challenges reside in: (1) the observational difficulties, (2) in the responses of the mobile sediments and the motion of the overlying fluid being both mutual and non-linear, and (3) in the fundamental connections to fluid turbulence, one of the great unsolved problems in classical physics. **