Assimilation of coastal acoustic tomography data using an unstructured triangular grid ocean model for water with complex coastlines and islands
Assimilation of coastal acoustic tomography data using an unstructured triangular grid ocean model for water with complex coastlines and islands
复制标题
使用非结构化三角网格海洋模型对具有复杂海岸线和岛屿的水域进行沿海声学层析成像数据同化
DOI：
10.1002/2017jc012715
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发表时间：
2017-09-01
影响因子：
3.6
通讯作者：
Zhang, Chuanzheng
中科院分区：
文献类型：
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作者：
Zhu, Ze-Nan;Zhu, Xiao-Hua;Zhang, Chuanzheng
我们首次使用集合卡尔曼滤波器方案将非结构化三角网格应用于有限体积社区海洋模型，以同化沿海声学断层扫描（CAT）数据。观测区域内岛屿周围的精细水平和垂直电流场结构均得到了良好的再现。与反演和模拟获得的速度相比，同化深度平均速度与独立声多普勒电流剖面仪（ADCP）数据具有更好的一致性。数据同化获得的深度平均水流速度与ADCP获得的深度平均水流速度的均方根差（RMSD）为0.07 m s(-1)，小于反演和模拟获得的相应差值（分别为0.12和0.17 m s(-1)）。与通过模拟获得的速度相比，同化的垂直层速度也表现出与 ADCP 更好的一致性。垂直层同化数据与ADCP数据之间的RMSD范围为0.02至0.14 m s(-1)，而模拟与ADCP数据之间的RMSD范围为0.08至0.27 m s(-1)。这些结果表明同化具有最高的准确性。涉及消除声音传输线的敏感性实验表明，丢失数据对同化的影响小于对反演的影响。消除CAT站的敏感性实验表明，4个CAT站的同化是本次实验中相对经济合理的程序。这些结果表明，与反演和模拟相比，非结构化三角网格CAT数据的数据同化在重建当前场方面更有效。
For the first time, we present the application of an unstructured triangular grid to the Finite-Volume Community Ocean Model using the ensemble Kalman filter scheme, to assimilate coastal acoustic tomography (CAT) data. The fine horizontal and vertical current field structures around the island inside the observation region were both reproduced well. The assimilated depth-averaged velocities had better agreement with the independent acoustic Doppler current profiler (ADCP) data than the velocities obtained by inversion and simulation. The root-mean-square difference (RMSD) between depth-averaged current velocities obtained by data assimilation and those obtained by ADCPs was 0.07 m s(-1), which was less than the corresponding difference obtained by inversion and simulation (0.12 and 0.17 m s(-1), respectively). The assimilated vertical layer velocities also exhibited better agreement with ADCP than the velocities obtained by simulation. RMSDs between assimilated and ADCP data in vertical layers ranged from 0.02 to 0.14 m s(-1), while RMSDs between simulation and ADCP data ranged from 0.08 to 0.27 m s(-1). These results indicate that assimilation had the highest accuracy. Sensitivity experiments involving the elimination of sound transmission lines showed that missing data had less impact on assimilation than on inversion. Sensitivity experiments involving the elimination of CAT stations showed that the assimilation with four CAT stations was the relatively economical and reasonable procedure in this experiment. These results indicate that, compared with inversion and simulation, data assimilation of CAT data with an unstructured triangular grid is more effective in reconstructing the current field.