A passive acoustic method for estimating the flow of underwater bubble gas emissions for shallow water areas has been proposed and tested. The method is based on the connection between the frequency of the acoustic signal produced by a gas bubble when it separates from the underwater outlet channel and the size of the bubble. In the conducted laboratory experiments acoustic signals with frequencies in the range from 2.7 to 0.4 kHz were recorded during generation of bubbles with a size from 2 to 15 mm within the fluid. The analysis of acoustic recordings made near existing shallow-water seeps in Laspi Bay showed a series of short audio signals produced by the released methane bubbles of 0.5–2s duration, grouped into packages containing approximately ten pulses. For the two investigated seeps, the frequency peaked at 1 and 1.4 kHz. According to a theoretical estimate, the bubbles generating such a signal are 7 and 5 mm in diameter, respectively. Taking the intensity of the bubble discharge into account, the calculated gas flows were 40 and 6 liters per day, respectively.

中文翻译：

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被动声学方法在浅水气泡气体排放检测与估算中的应用

已经提出并测试了一种用于估计浅水区水下气泡气体排放流量的无源声学方法。该方法基于气泡从水下出口通道分离时产生的声音信号的频率与气泡大小之间的联系。在进行的实验室实验中，在流体中产生大小为2至15 mm的气泡期间，记录了频率范围为2.7至0.4 kHz的声音信号。对Laspi湾现有浅水渗漏附近的声学记录进行的分析显示，由释放的持续时间为0.5–2s的甲烷气泡产生的一系列短音频信号，被分组为包含大约十个脉冲的包装。对于两个调查的渗漏，频率在1和1.4 kHz达到峰值。根据理论估计，产生这种信号的气泡的直径分别为7毫米和5毫米。考虑到气泡排放的强度，计算出的气体流量分别为每天40升和6升。