Experiment of acoustic tomography under ice in Songhua River basin

Coastal acoustic tomography is one of the important means currently used in river offshore observation. It can obtain important hydrological information such as temperature, salinity and flow velocity of the observed waters. In this paper, a coastal acoustic tomography experiment was carried out to measure current under ice in Songhua River waters. As the first subglacial acoustic tomography experiment, we set up three acoustic tomography stations near Tianhe Bridge in the Songhua River basin, and each station is equipped with a set of coastal acoustic tomography devices. The placement depth of the transducer under the ice is 5m, and the frequency of the transmitted signal is 25kHz. The cross section velocity is calculated by the time difference of the reciprocal acoustic signal propagation between several stations, so as to calculate the cross section flow for comparison with the data of the official hydrological station. This experiment is the first attempt at the application of coastal acoustic tomography under ice at home and abroad, and the result of the experiment is very ideal. The experiment of acoustic tomography under ice is feasible and we can get accurate flow data through the under ice acoustic tomography experiment. The results prove that the coastal acoustic tomography technology has a very broad application prospect in the flow monitoring of the subglacial basin.