2014年4~5月期间,搭乘“东方红二号”科考船(R/V)对黄海和渤海大气中凝结核数浓度(Concentrations of atmospheric particles,Ncn)、云凝结核数浓度(Concentrations of cloudcondensation nuclei,Nccn)、污染气体(SO2,O3)浓度以及大气...2014年4~5月期间,搭乘“东方红二号”科考船(R/V)对黄海和渤海大气中凝结核数浓度(Concentrations of atmospheric particles,Ncn)、云凝结核数浓度(Concentrations of cloudcondensation nuclei,Nccn)、污染气体(SO2,O3)浓度以及大气颗粒物粒径分布进行了走航观测。观测结果显示,在整个航次期间,Ncn的变化范围为(2.7~57.6)×10^3 cm^-3,平均值为(12.6±7.0)×10^3 cm^-3。Ncn和Nccn在渤海最高,北黄海次之,南黄海最低,其中渤海的Ncn比北黄海和南黄海的Ncn分别高出41%和85%,在0.2%过饱和度(Supersaturation,SS)0.4%SS和1.0%SS下,渤海的Nccn比北黄海和南黄海的Nccn分别高出8%和17%、23%和30%以及38%和50%。南黄海在0.2%SS、0.4%SS和1.0%SS对应的活化效率(Activation ratio,AR)分别为0.25±0.08、0.52±0.14和0.56±0.14;北黄海和渤海在0.2%SS、0.4%SS和1.0%SS下对应的AR分别为0.24±0.10和0.17±0.07,0.47±0.15和0.38±0.16以及0.53±0.17和0.50±0.19。AR值在渤海最小,北黄海次之,南黄海最大,这可能是因为在不同海域气溶胶颗粒物粒径分布的差异,导致了气溶胶颗粒物活化为CCN效率的不同。此外,观测到一次新粒子生成(New particle formation,NPF)事件,当新粒子的中值粒径增长到40 nm左右时,Nccn在1.0%SS下升高127%,0.4%SS下升高36%,0.2%SS下没有变化。最后,探究了Ncn与SO2在近海大气中的关系,即:Ncn=1.7×10^3 SO2+3.4×10^3。展开更多
An air gun generates acoustic signals for seismic exploration by releasing a high-pressure gas.A large error is always gradually introduced into the ideal-gas model when the pressure in the air-gun chamber exceeds 100...An air gun generates acoustic signals for seismic exploration by releasing a high-pressure gas.A large error is always gradually introduced into the ideal-gas model when the pressure in the air-gun chamber exceeds 100 atm.In the van der Waals non-ideal-gas theory,the gas in the air gun can be regarded as an actual gas,and the error is less than 2%.The van der Waals model is established in combination with the quasi-static open thermodynamic system and bubble-motion equation by considering the bubble rise,bubble interaction,and throttling eff ect.The mismatch between the van der Waals and ideal-gas models is related to the pressure.Theoretically,under high-pressure conditions,the van der Waals air-gun model yields results that are closer to the measured results.Marine vertical cables are extended to the seafl oor using steel cables that connect the cement blocks,but the corresponding hydrophones are suspended in the seawater.Thus,noise associated with ships,ocean surges,and coupling problems is avoided,and the signal-to-noise ratio and resolution of marine seismic data are improved.This acquisition method satisfies the conditions of recording air-gun far-fi eld wavelets.According to an actual vertical-cable observation system,the van der Waals air-gun model is used to model the wavelet of different azimuth and take-off angles.The characteristics of the experimental and simulated data demonstrate good agreement,which indicates that the van der Waals method is accurate and reliable.The accuracy of the model is directly related to the resolution,thus aff ecting the resolution ability of the stratum.展开更多
基金This work has been supported by the following:the National Natural Science Foundation of China(No.91958206,91858215)the National Key Research and Development Program Pilot Project(No.2018YFC1405901,2017YFC0307401)+1 种基金the Fundamental Research Funds for the Central Universities(No.201964016)the Marine Geological Survey Program of China Geological Survey(No.DD20190819).
文摘An air gun generates acoustic signals for seismic exploration by releasing a high-pressure gas.A large error is always gradually introduced into the ideal-gas model when the pressure in the air-gun chamber exceeds 100 atm.In the van der Waals non-ideal-gas theory,the gas in the air gun can be regarded as an actual gas,and the error is less than 2%.The van der Waals model is established in combination with the quasi-static open thermodynamic system and bubble-motion equation by considering the bubble rise,bubble interaction,and throttling eff ect.The mismatch between the van der Waals and ideal-gas models is related to the pressure.Theoretically,under high-pressure conditions,the van der Waals air-gun model yields results that are closer to the measured results.Marine vertical cables are extended to the seafl oor using steel cables that connect the cement blocks,but the corresponding hydrophones are suspended in the seawater.Thus,noise associated with ships,ocean surges,and coupling problems is avoided,and the signal-to-noise ratio and resolution of marine seismic data are improved.This acquisition method satisfies the conditions of recording air-gun far-fi eld wavelets.According to an actual vertical-cable observation system,the van der Waals air-gun model is used to model the wavelet of different azimuth and take-off angles.The characteristics of the experimental and simulated data demonstrate good agreement,which indicates that the van der Waals method is accurate and reliable.The accuracy of the model is directly related to the resolution,thus aff ecting the resolution ability of the stratum.
