Study Of A Coastal Acoustic Laminar System For Flow Measurement Under Ice

With the gradual development of the Arctic shipping lanes,the survey of the polar environment is imminent.However,due to the presence of large amounts of ice and the influence of the harsh climate,traditional measurement methods are difficult to achieve results.Coastal acoustic tomography is currently the main method of offshore observation,and by placing a small number of acoustic stations,a large amount of acoustic data can be obtained continuously to invert the environmental parameters of the target basin.It is the main objective of this paper to apply coastal acoustic tomography to the subglacial environment and to investigate the coastal acoustic tomography system for the purpose of successful subglacial current measurement.Firstly,we study the characteristics of under-ice sound propagation in the Songhua River basin,combine Bellhop to simulate the sound propagation attenuation and sound trajectory,and set up the coastal acoustic tomography system according to the characteristics of the simulation results that are different from the general water sound propagation.The experiments were carried out near the Tianhe Bridge of the Songhua River.Three acoustic tomography stations were set up,and the river velocity and flow results were obtained by using the double line measurement method.Secondly,for the experiments encountered in the snowy weather interference experiments,using the electric wave timing clock system as a supplement to the acoustic stratification system clock system,and the stability of the electric wave timing measurement experiments and GPS timing comparison experiments,to verify the electric wave timing clock system can not be affected by the bad weather and meet the acoustic stratification system calibration accuracy requirements.Through the above,it is shown that it is feasible to apply the coastal acoustic tomography system to the field of under-ice current measurement,and it can be achieved without the influence of the harsh climate in the cold environment,and the coastal acoustic tomography technology is expected to be called an important acoustic method for polar survey.