西太平洋夏季三类声速环境下的会聚区特性比较

Comparison of Convergence Zone Features Under Three Different Hydrological Environment in the West Pacific Ocean in Summer

利用Argo剖面数据和水声学数值模型,分析了西太平洋夏季在热带海区（Ⅰ型）、亚热带南部海区（Ⅱ型）和亚热带北部海区（Ⅲ型）三类典型声速环境下的会聚区特性。声场计算结果表明,声速环境的区域性差异及声源深度的变化对会聚区声场特性有明显影响。当声源深度为20m时,热带海区会聚区距离较远,第一会聚区约为65km,超出亚热带海区约5km;当声源深度为200m时,亚热带北部海区会聚区距离较远,第一会聚区约为60km,亚热带南部海区、热带海区依次递减约5km。Ⅰ型和III型剖面在特定的声源深度条件下出现波导型声场,当声源位于表层时热带海区产生表面波导,当声源位于次表层时亚热带北部海区产生次表层波导,对于1kHz的声波,波导深度范围内的传播损失比波导深度以外高出10~20dB。

Features of convergence zone （CZ） in the tropical Pacific （type Ⅰ）, south subtropical Pacific （type Ⅱ） and north subtropical Pacific （type Ⅲ） in summer are compared by the Argo profiler data and a coustic numerical model. The results show that CZ field can be obviously influenced by the sound speed environment varieties. When the sound source is located 20 m beneath the surface, CZ in tropical area is furthest. The first CZ is about 65 km, which is 5 km further than that in the subtropical area. When a source is located in 200 m depth, CZ in the north subtropical area is furthest. The first CZ position is a- bout 60 km, which is 5 km further than that in north subtropical and tropical areas. Profiles of type Ⅰ and type Ⅲ can induce a duct field. Surface duct exists in tropical area when the source is in the surface layer, and the subsurface duct exists in the subtropical area when the source is in the subsurface layer. The sound level in the duct area is 10~20 dB higher than that in the non-duct area （sound frequency 1 kHz）.