水下声学浮标南中国海海洋环境噪声实测分析*

海洋环境噪声是多种自然噪声和人为噪声的复杂组合,其谱级大小和频率组成是影响声纳系统探测性能的重要参数,由于海洋环境噪声时空域特性是非常复杂的,因此需要对海洋环境噪声进行长时间和大范围的观测才足以分析其特性。本文通过在多剖面水下浮标平台基础上集成声学测量系统,研制出了一种具有海洋环境噪声监测能力的水下声学浮标平台,该浮标平台可多次上浮、下潜,具备原位坐底和定深漂流两种工作模式,能够连续观测海洋环境噪声时长多达几个月。利用2019年8月在南海海区组织的多台水下声学浮标组网试验数据,分析了不同频率海洋环境噪声谱级随时间变化特性,数据处理结果符合海洋环境噪声典型变化规律,试验表明,水下声学浮标可作为一种潜在的优势水下无人移动平台,用于长期监测海洋环境噪声特性。

Measurement and analysis of ambient noise in the South China Sea based on underwater acoustic buoy

Ocean ambient noise is a complex combination of many types of natural and anthropogenic noises. The spectrum levels and frequency composition are very important in the detection performance of a sonar system. Since the spatial and temporal characteristics are complicated, it is necessary to conduct long-term and large scales monitoring of the ambient noise to analyze its properties. Thus, we designed and developed an underwater acoustic buoy with acoustic measuring system to sample the ambient noise on spatial and temporal. The acoustic buoy can be used for multiple floating and diving, and has two working mode with in-situ bottoming and deep-draining. The maximum endurance is typically a few months in the ocean. Using the networking experiment data collected by several underwater acoustic buoys, which were arranged in a certain area in the South China Sea in August 2019, this study investigated the different frequencies of ambient sea noise spectrum level change with time. The data processing results are consistent with the typical variation law of ambient noise. The results of this study indicated that acoustic buoy as a potential underwater unmanned platform could be used in the future for long-term monitoring of ambient noise properties.