Fig. 1. Sound speed profiles (thin line) and average sound speed profile (rough line) measured by CTD.CTD测得的声速剖面(细线)和平均声速(粗线)

Fig. 2. Temperature, salinity and buoyancy frequency profile.温度、盐度以及浮力频率剖面

Fig. 3. Comparison of the sound speed profile bases obtained by different methods (black line, HMB; red line, EOF).不同方法获得的声速剖面展开基比较(黑线, HMB方法; 红线, EOF方法)

Fig. 4. Error analysis of different samples.不同样本重构效果的误差分析

Fig. 5. The 8th sound speed profile reconstruction.第8号声速剖面重构

Fig. 6. Analysis of transmission loss calculated by sound speed profiles (dB): (a) CTD measurement; (b) HMB reconstruction; (c) EOF reconstruction.声速剖面计算传播分析(单位: dB)　(a) CTD测量; (b) HMB重构; (c) EOF重构

Fig. 7. Amplitude of the first two modes.前两阶模态振幅

Fig. 8. Variations of the depth at a sound speed of 1525 m/s and the first-order projection coefficient with samples.1525 m/s等声速线深度和第一阶投影系数随样本的变化

Fig. 9. Variations of the sound speed gradient and the second-order projection coefficient with samples.声速梯度和第二阶投影系数随样本的变化

Fig. 10. Inversion process.反演流程

Fig. 11. Inversion results at different ranges: (a) 10.2 km; (b) 10.2 km; (c)12 km.不同距离的反演结果　(a) 10.2 km; (b) 10.2 km; (c) 12 km

Fig. 12. Probability distribution for the three inversion parameters (the red line is the optimum value for the objective function).3个反演参数的边缘概率密度分布 (红线为代价函数最优值对应参数)

Fig. 13. Transmission loss predicted and measured.传播损失预报与观测值