基于声学技术的红沿河核电站附近海域夏季水母通量测量

大量水母涌入核电站取水口会对核电冷源取水安全造成严重威胁,为把握夏季红沿河核电站附近海域水母的密度和基本运动规律,分别于2017年7、8、9月在红沿河核电站附近海域使用同时搭载科学探鱼仪(120、200 kHz)和多普勒流速剖面仪(ADCP)的调查船,沿垂直等深线方向进行25 h、10 n mile长垂直断面往复走航水母资源声学调查和潮流观测,并在次日昼间使用多锚张网进行水母样本采集;利用频差处理技术分离海月水母Aurelia aurita、沙蛰Nemopilema nomurai及浮游动物的叠加声学散射信号,使用回波积分法推定沙蛰和海月水母密度,并结合潮流数据计算水母通过调查断面的通量。结果表明:2017年7、8、9月份潮流流速最大值分别为0.80、0.70、0.65 m/s,流速随涨潮和落潮周期逐渐增大和减小;海月水母的平均密度高于沙蛰,二者7月分别为9.79、2.30 ind./m²,8月分别为11.05、1.51 ind./m²,9月分别为0.82、0.32 ind./m²;海月水母在7、8、9月份涨潮时平均通量分别为5.85、3.53、0.40 ind./(s·m²),落潮时平均通量分别为-2.84、-6.07、-0.36 ind./(s·m²),沙蜇在7、8、9月份涨潮时平均通量分别为1.45、0.44、0.17 ind./(s·m²),落潮时平均通量分别为-0.86、-0.76、-0.13 ind./(s·m²)。研究表明:水母通量与涨落潮流速变化具有相关性,能够较好地反映水母的移动趋势,并可作为核电站冷源生物监测预警的重要指标;水母在取水口外侧海域具有随机分布的特性,适合声学浮标监测。

Flux measurement of jellyfish near Hongyanhe Nuclear Power Station area in summer by using acoustic methods

The influx of jellyfish flooding into the water intake of the nuclear power plants threatens the safety of the water taken of the nuclear powder cold source.In order to grasp the density and basic movement of jellyfish in the sea near the Hongyanhe Nuclear Power Station,a survey ship equipped with scientific fishfinder(120,200 kHz)and Doppler velocity profiler(ADCP)was used in the waters near the Hongyanhe,and the survey ship was carried out for 25 h along the vertical isobath in the summer of 2017,July,August,and September.Acoustic resource survey and tidal current observation of 10 n mile vertical section was conducted reciprocating navigation,and samples of jellyfish were collected by multi-anchor nets in the next day.The frequency difference processing technology was used to separate the superimposed acoustic scattering signals of jellyfish Aurelia aurita,Nemopilema nomurai and other plankton.The echo integration method was used to estimate the density of Aurelia aurita and Nemopilema nomurai,and the flux of the jellyfish through the survey section was calculated based on the tidal data.The results showed that the maximum flow velocity was shown to be 0.80 m/s in July,0.70 m/s in August and 0.65 m/s in September.The speed of the ocean current was gradually increased and decreased with the cycle of rising and falling tides.There was higher average density of Aurelia aurita than that of Nemopilema nomurai,9.79 and 2.30 ind./m² in July;11.05 and 1.51 ind./m² in August;0.82 and 0.32 ind./m² in September.Aurelia aurita had average fluxes of 5.85 ind./(s·m²)in July,3.53 ind./(s·m²),in August and 0.40 ind./(s·m²)in September at high tides.The average flux was-2.84 ind./(s·m²)in July,-6.07 ind./(s·m²)in August,and-0.36 ind./(s·m²)in September at low tide.The average flux of Nemopilema nomurai was 1.45 ind./(s·m²)in July,0.44 ind./(s·m²)in August and 0.17 ind./(s·m²)in September;the average flux at low tide was-0.86 ind./(s·m²)in July,-0.76 ind./(s·m²)in August,and-0.13 ind./(s·m²)in September at high tides,indicating that that the flux of jellyfish was correlated with changes in the speed of fluctuations and tidal currents,which can well reflect the movement trend of jellyfish.Jellyfish as an important indicator for the monitoring and early warning of cold source biology in nuclear power plants is featured by random distribution in the sea outside the water intake,which is suitable for acoustic buoy monitoring.