中文摘要：

分析不同海底参数对环境噪声垂向空间特性的敏感度，根据海底密度对环境噪声垂直指向性的小掠射角部分不敏感，而对等效海底损失的大掠射角部分相对敏感的特点，提出了一种海洋环境噪声分步反演地声参数方法：先用环境噪声垂直指向性小掠射角部分反演海底声速、衰减；之后利用大掠射角部分来反演海底密度。仿真算例和海上实验数据处理结果验证了该方法的有效性。结果表明：分步反演加强了匹配物理量对海底参数敏感部分的关注，在反演结果精度（海底密度）以及反演效率上都有所改善，具有一定可行性。

英文摘要：

Seabed parameters sensitivity to the vertical spatial characteristics of ocean ambient noise field is analyzed. A multi-step method of geo-acoustic inversion is proposed based on the characteristics that seabed density is insensitive to the vertical directionality of ambient noise below the critical angle and relatively sensitive to the seabed reflection loss at steeper angles. Seabed sound speed and attenuation are inverted by the vertical array response of ambient noise below the critical angle first, and then density is inverted by the part at steeper angles. The simulations and experiment data processing are performed to validate this method.The results was demonstrated that the multi-step method improves the inversion efficiency and accuracy of seabed density because of the enforced focus on the sensitive parts of matching physical quantities and it is feasible.