Acoustic Diagnosis of Internal Waves on the Black Sea Shelf According to Tomographic Experiment Data

On the northeastern shelf of the Black Sea in 2010, a tomographic experiment was carried out on the counterpropagation of phase-shift keyed acoustic signals. During the day, the time responses of the medium were measured during the emission and reception of high-frequency complex phase-shift keyed signals from three bottom-moored transceivers located at the corners of an equilateral triangle with sides of about 1100 m. The transceivers were at a distance of >2 km from Golubaya Bay at a depth of about 40 m. Nearby, a thermistor chain was moored to record internal waves. Based on the data on the temporal variability of the responses of the medium to acoustic signals, information about the internal waves present in the water area was reconstructed using the method of consistent time responses. A temporal sampling of the vertical displacements of the thermocline was obtained, in which short-period waves with a height of 0.5–1 m and a period from 5 to 15–20 min were found. Comparison of acoustic measurements with independent contact measurements of internal waves revealed their good mutual agreement. On the whole, the results of the acoustic experiment showed the possibility of successfully using acoustic tomography to study the dynamics of waters for shallow-water conditions.