Coastal and Continental Shelf Oceanography

目标：长期目标是改进对移动床动态调整以适应近岸和大陆架环境中的波流联合强迫的预测。短期的主要目标是利用和发展先进的声学遥感系统，以研究活跃输运条件下底部边界层中的动量和泥沙的湍流通量，以及高流量潮汐水道中的湍流的极值统计。*方法：(1)将在实验室和现场实验中使用自行开发的最先进的、高分辨率、湍流分辨率的多频率声学多普勒剖面系统，以遥测不断演变的移动床上方的速度、湍流和泥沙通量的时空结构。(2)利用现场快速反应湍流探头和多种先进的声学多普勒仪，在高流量潮汐水道中对湍流在1秒到1个月的时间尺度上的变化进行了直接和远程的研究。(3)将使用仪表化机器人水面飞行器研究风暴期间近岸区域和内大陆架波流强迫的移动床面调整，以及沙丘和巨型沙丘对高流量潮汐水道强烈湍流和逆流条件的调整。*意义：流动的海底沉积物对流体强迫变异性的调节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与海岸线和沿海基础设施保护有关的海底变化；(B)传统上包括海床稳定性对利用河流涡轮机进行可再生水力发电的高流量潮汐水道潜在开发的影响；(B)湍流和海床调整对沿海和整个大陆架环境条件的可预测性的影响；(C)通过沉积记录改进对古环境条件的解释的可能性。挑战在于：(1)观测困难，(2)流动沉积物和上覆流体运动的相互和非线性的响应，以及(3)与流体湍流的基本联系，这是经典物理中尚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. **