Coastal and continental shelf oceanography

沿海和大陆架海洋学

• 批准号: 198845-2007
• 负责人: Hay, Alexander
• 金额: $ 5.32万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 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=363632
• 关键词: Coastal; continental; shelf; oceanography

Objectives: The long-term objective is to predict the dynamic adjustment of the mobile seabed to combined wave-current forcing. The focus of this proposal is the role of bottom stress, and non-linear wave-wave and wave-current interactions, in the adjustment process. Primary objectives are improved knowledge and understanding of: (1) the relationships between wave energy, near-bed fluid turbulence, bottom stress and bed state occurrence; (2) the vertical sediment flux balance and sediment entrainment; (3) the role of higher-order velocity moments in the horizontal sediment flux; and (4) bedform genesis, growth, migration and decay.     Approach: Acoustic and optical remote sensing technologies are used to obtain comprehensive seabed imagery and velocity, turbulence and suspended sediment concentration profiles spanning the bottom boundary layer. New initiatives include: a newly-developed multi-frequency acoustic Doppler system for remotely measuring velocity, turbulence and sediment flux profiles within the thin wave bottom boundary layer; a laboratory facility for oscillatory-flow boundary layer studies above both fixed-grain and mobile sediment beds; and the use of these sensors in deep-ocean observing systems.         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 the applied science and societal needs for more accurate predictions of seabed change, in the effects of seabed adjustment on the predictability of ocean dynamics, and in the potential for improved interpretation of paleo-environmental conditions through the sedimentary record. The challenge resides in the observational difficulties, in the responses of the mobile sediments and the fluid motions being both mutual and non-linear, and in the fundamental connections to fluid turbulence, one of the great unsolved problems in modern physics. Particular to the coastal and shelf regions of the ocean, relative to other mobile bed environments (rivers, deserts, snow fields), is the central role of forcing by surface gravity waves.

目标：长期目标是预测移动海底对组合波流强迫的动态调整，该提案的重点是底部应力以及非线性波波和波流相互作用的作用。调整过程的主要目标是提高对以下方面的认识和理解：(1) 波浪能、近床流体湍流、底部应力和床状态发生之间的关系；(2) 垂直泥沙通量平衡和泥沙夹带；高阶速度矩的作用水平沉积物通量；(4) 地床形成、生长、迁移和腐烂。方法：利用声学和光学遥感技术获取跨越底部边界层的全面海底图像和速度、湍流和悬浮沉积物浓度剖面。 ：新开发的多频声多普勒系统，用于远程测量薄波底部边界层内的速度、湍流和沉积物通量剖面；用于研究固定颗粒上方振荡流边界层的实验室设施；和移动沉积物床；以及这些传感器在深海观测系统中的使用意义：移动海底沉积物对流体强迫变化的调整是现代海洋科学和社会面临的重要挑战之一。需要更准确地预测海底变化、海底调整对海洋动力学可预测性的影响，以及通过沉积记录改进对古环境条件的解释的潜力。流动沉积物和流体运动的响应是相互的和非线性的，以及与流体湍流的基本联系是现代物理学中尚未解决的重大问题之一，特别是在沿海和陆架地区。相对于其他移动床环境（河流、沙漠、雪原），海洋是表面重力波作用的核心。