Turbulent mixing on continental shelves plays roles in the structure and dynamics of marine ecosystems, nutrient cycling, primary production and dispersion of pollutants. Describing and understanding internal wave dynamics enables improved mapping of mixing over continental shelves, especially in complex environments where many processes may interact, such as in upwelling systems. This paper describes internal wave propagation and dissipation in the Moroccan upwelling system using a comprehensive set of hydrographic observations made during two in situ surveys. The acoustic backscatter of the echosounder is shown to be a rapid and convenient survey tool for detecting internal solitary waves (ISWs) on large spatial scales, through the high-frequency oscillation of the zooplankton layer during nighttime conditions. Along ISW trains, enhanced diapycnal mixing episodes are observed with increased dissipation coefficients in the thermocline (O(10^-7 W.kg^-1)), associated with overturning up to 6 m. Mixing due to internal wave soliton packets shows large spatial and temporal variability, but contributes to the overall mixing processes and is responsible for large intermittent variations in the thermocline position. The joint use of a multifrequency echosounder and a current profiler ADCP allows mixing to be quantified (via the Richardson number) on large spatial scales. Validation and use of this method in other coastal regions could be useful to determine regional mixing parameterization in numerical models.

大陆架上的湍流混合在海洋生态系统的结构和动力学、养分循环、初级生产和污染物的扩散中发挥作用。描述和理解内波动力学可以改进大陆架混合的映射，特别是在许多过程可能相互作用的复杂环境中，例如在上升流系统中。本文使用在两次原位调查期间进行的一组综合水文观测描述了摩洛哥上升流系统中的内部波传播和消散。通过夜间条件下浮游动物层的高频振荡，回声测深仪的声学反向散射被证明是一种快速方便的调查工具，用于在大空间尺度上检测内部孤立波 (ISW)。沿着ISW火车，^-7  W.kg ^-1 ))，与高达 6 m 的倾覆有关。由内波孤子包引起的混合显示出很大的空间和时间变化，但有助于整个混合过程，并导致温跃层位置的大间歇变化。多频测深仪和电流剖面仪 ADCP 的联合使用允许在大空间尺度上量化（通过理查森数）混合。在其他沿海地区验证和使用这种方法可能有助于确定数值模型中的区域混合参数化。