Abstract The Port of Saint John is a highly stratified, hyper-tidal estuary that requires frequent hydrographic surveys to ensure that minimum under-keel clearances are maintained and to monitor dredge operations. The potential achievable accuracy and efficiency of a multibeam sonar survey correlates to the knowledge of the physical oceanographic conditions of the harbour. A high-resolution baroclinic hydrodynamic model of the Port of Saint John was constructed to understand the dynamic physical oceanographic environment over four periods representing the limits in river flow conditions. The model provides time-varying outputs of temperature and salinity at predefined depth intervals over the domain. Sound speed is derived from the model output and is used for ray-tracing multibeam sonar data and survey planning to minimize refraction errors. Ray-tracing depth error statistics are calculated from Moving Vessel Profiler (MVP) temperature and salinity casts and used to evaluate the model skill. Results demonstrate that the model can be used to replace observed sound speed profiles and stay within depth accuracy specifications within a swath width of 60 degrees, or more, for most of the year throughout the harbour. Uncertainty increases for swath widths of more than 55 degrees during the most severe stratification of the spring freshet.

中文翻译：

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高度分层河口水动力模型的多波束声纳射线追踪不确定性评估

摘要 圣约翰港是一个高度分层的潮汐河口，需要经常进行水文调查，以确保保持最小的龙骨下间隙并监控疏浚作业。多波束声纳勘测的潜在可实现精度和效率与港口物理海洋条件的知识相关。构建了圣约翰港的高分辨率斜压水动力模型，以了解代表河流流动条件限制的四个时期的动态物理海洋环境。该模型在域内以预定义的深度间隔提供温度和盐度的时变输出。声速源自模型输出，用于光线追踪多波束声纳数据和勘测规划，以最大限度地减少折射误差。光线追踪深度误差统计是根据移动血管剖面仪 (MVP) 温度和盐度模型计算得出的，用于评估模型技能。结果表明，该模型可用于替换观察到的声速剖面，并在整个港口一年中的大部分时间里保持在 60 度或更大的条带宽度内的深度精度规范内。在春季新鲜的最严重分层期间，超过 55 度的条带宽度的不确定性增加。全年大部分时间都在整个海港。在春季新鲜的最严重分层期间，超过 55 度的条带宽度的不确定性增加。全年大部分时间都在整个海港。在春季新鲜的最严重分层期间，超过 55 度的条带宽度的不确定性增加。