The environmental safety of the Russian arctic shelf waters and improving the safety of marine ecosystems by reducing the noise pollution
Authors:   Krylov State Research Centre, St. Petersburg, Russia, Kalyu V.A. , Smirnov D.A. ,   Krylov State Research Centre, St. Petersburg, Russia, Tarovik V.I. ,   Krylov State Research Centre, St. Petersburg, Russia, Sergeev M.S. ,   Krylov State Research Centre, St. Petersburg, Russia, Petrova V.V. ,   Krylov State Research Centre, St. Petersburg, Russia
Published: June 2023

Object and purpose of research. Ensuring the environmental safety of the Russian shelf waters requires constant development of methods and technologies related to monitoring, quantitative assessment and reduction of the harmful effects of pollution sources. During the industrial and transport development of the water area of the Northern Sea Route (NSR), an intensive increase of underwater noise is observed. Obtaining an adequate picture of the impact of underwater noise sources on representatives of the marine ecosystem creates a need to involve more and more modern and accurate measurement techniques. The article describes the draft methods for measuring the self-noise of carrier vessel and underwater noise of a selected marine equipment object, which were developed in order to identify the degree of impact of noise pollution over to the ecological situation in the considered water area. Materials and methods. An hydro acoustic signals contains the self-noise of measuring vessel, the noise of an object of marine industrial equipment (OMIE) and the noise of the water area where acoustic tests are going on. This acoustic signals are perceived by combined sound pressure and sound pressure gradient transducers, as well as by an omnidirectional hydrophone, located in the receiving system , and are converted into electrical signals transmitted via the main cable to the onboard post of the measuring vessel. Signals are sent to the hydro acoustic guidance beacon via the same cable to control the operation of this beacon. The information processing procedure is set out in the SIGAK VP Operation Manual (MGFK.411711.327 RE). The main purpose of the primary processing is to obtain 1/3-octave spectra and levels of underwater noise generated by the tested carrier vessel or OMIE, as well as the noise of the water area where these tests are carried out. In accordance with the accepted classification, the method of measuring sound pressure levels using a hydro acoustic complex according to this technique refers to indirect methods with single observations. Main results. In the course of the work, preliminary methods for measuring the self-noise of measuring vessel and underwater noise of a selected marine industrial object were developed. To measure the levels of underwater noise in 1/3-octave frequency bands in the range from 5 Hz to 10,000 Hz, within the framework of the draft methods, it is planned to use a stationary measuring hydro acoustic complex with a vector receiver from the GIK-VP. The signal processing algorithms are based on the spatial-frequency filtering of the acoustic power flux density components, which makes it possible to protect the measurement information from interference signals whose propagation direction does not coincide with the direction to the measured object. Conclusion. The results obtained in the form of implemented preliminary methods are important for the creation of regulatory documentation for the regulation of technogenic underwater noise in the waters of the Russian jurisdiction, reducing the intensity of noise pollution and the detrimental impact over to marine ecosystems. The article targeting the support at the stages of acoustical marine technical design, construction and operation of offshore industrial facilities and ships of various types, acoustic monitoring of the compliance of marine equipment with international standards for underwater noise.