基于沿海声层析和高频地波雷达联合观测的三维流场研究

Both Coastal Acoustic Tomography (CAT) and High Frequency ground wave Radar (HF-Radar) are two of the most efficient and feasible techniques for mapping the continuously varying current fields over a large area in coastal regions. However, the observation though merely CAT or HF-radar can only obtain the depth-averaged or surface current fields. It is hard to achieve the research objectives in coastal seas where the tidal current structures are complex and have obvious three-dimensional characteristics by using the horizontal current data. The combination of CAT and HF-radar for synchronous observation is expected to obtain the continuous three-dimensional current field structures over a large area. But so far, there are still no observation or current field researches which base on the fusion of these two techniques. The project plans to select the outer bay of Xiangshan Bay, which is still unclear in the tidal current structures, as the demonstration region, and take the lead in conducting CAT and HF-radar synchronous observation experiments. Thus, the high precision three-dimensional current fields will be reconstructed by using the data assimilation method with multi–source data. Furthermore, the dynamic mechanisms of tidal and residual currents in Xiangshan Bay will also be clarified. The implementation of this project can provide new methods for hydrological monitoring, environmental protection and disaster prevention in coastal regions.

沿海声层析和高频地波雷达是获取近岸大范围连续变化流场的为数不多的两个高效可行手段。然而单一的沿海声层析或高频地波雷达观测仅能获取垂向平均或表层流场，无法应对潮流复杂、三维特征强的近岸海区的研究需求。将沿海声层析和高频地波雷达结合起来开展同步观测，则有望获取大范围连续的三维流场结构。但到目前为止，尚未见两者融合观测和后续流场联合反演的实际案例。本项目拟选取潮流结构尚不甚明了的象山港外湾作为研究海区，率先开展沿海声层析和高频地波雷达同步观测实验，实现近岸大范围三维流场的观测，进一步进行多源数据融合的三维流场同化研究，获取观测区域高精度的三维流场结构，并阐明研究海区潮流和余流的动力机制。本项目的实施，可为近岸水文监测、环境保护和防灾减灾等提供新的技术手段。

沿海声层析和高频地波雷达是获取近岸大范围连续变化流场的为数不多的两个高效可行手段。将沿海声层析和高频地波雷达结合起来开展同步观测，可以获取大范围连续的三维流场结构。但到目前为止，尚未见两者融合观测和流场联合反演的实际案例。.通过本项目的研究，选取象山港外湾为示范海区率先进行了声层析和地波雷达同步观测实验，成功实现了近岸大范围三维流场的观测并获取了两者的观测数据。进一步，我们还克服了多源异构流场数据同步同化的难题，将声层析观测的断面平均流速数据和地波雷达观测的表层径向流速数据同步同化到三维水动力海洋数值模式中，获取了观测区域高精度的三维流场结构。最后通过调和分析等方法，获取了示范海区的潮流、余流的三维结构。同样，项目组还基于声层析等观测数据探讨了象山港、胶州湾等近岸海区的非线性潮、余流等的动力机制。项目执行期间共发表发表16篇学术论文，其中包括JGR、GRL等海洋学主流杂志。.总体而言，本项目的研究体现了沿海声层析技术配合地波雷达对潮流场观测的优越之处，为沿海复杂地形下的流场观测和反演提供了新的范例。该成果有望进一步实现实时监测和同化预报等业务化应用，从而为近岸航运、污染物扩散追踪等提供服务。