Development of a system for monitoring and assessment of underwater sound

2020 ◽  
Author(s):  
Veselka Marinova ◽  
Asen Stefanov
Keyword(s):  
Marine Environment ◽  
Point Sources ◽  
Anthropogenic Sources ◽  
Simulation Tool ◽  
Underwater Sound ◽  
Underwater Noise ◽  
Marine Life ◽  
Environmental Status ◽  
Noise Impact ◽  
Sound Maps

<p>The Bulgarian Black Sea coast is an area with intense human activity, but also there is a complex ecosystem. Several anthropogenic sources generate loud sound levels in this area. The two most wide spread are maritime transport and hydrocarbon exploration and exploitation in the Bulgarian offshore sector. Underwater sound may have negative impact on animals in the Bulgarian waters that are sensitive to sound, such as marine mammals and certain fish species. </p><p>The knowledge of ambient noise levels is very important for the characterization of the environmental status with regard to the European Marine Strategy Framework Directive (MSFD). The directive is aiming at a more effective protection of the marine environment including the protection of marine life exposed to noise, and the improvement of the health of the marine environment as a whole.</p><p>To estimate this impact the ocean technologies department of Bulgarian Institute of Oceanology developed a system to monitor the sound generated by marine activities following the TSG Noise guidance. The aim was to provide an integrated solution to monitor and asses the noise impact of ship traffic or other marine activities. The development was funded by program BG02 "Integrated management of marine and inland waters" financed by the financial mechanism of the European economic Area (EEA FM) 2009-2014.</p><p>The system consists of monitoring and simulation components. The combination of numerical modelling and noise measurements at selected locations offers a credible solution to the problem of underwater noise monitoring. The monitoring component comprises an array of passive sound recorders, equipped with hydrophones, self-contained power supplies, data acquisition and storage electronics. The simulation tool is in development. Suitable modelling approaches, modelling scenarios, and acoustic model input values are being selected and applied for the most important sources of sound and for underwater sound propagation in the Bulgarian waters. The tool computes sound maps produced by multiple noise point sources, as input for assessment of the environmental status. For optimum results, the simulation tool will be validated using acoustic measurements provided by the monitoring tool.</p><p>Future work includes development of a post-processing tool of the sound maps to obtain indicators relevant to both the noise anthropogenic pressure and biological effect of underwater noise impact on marine life.</p>

STUDY AND APPLICATION OF UNDERWATER NOISE IMPACT IN COASTAL REGION OFF WESTERN TAIWAN

2014 ◽  
Vol 22 (01) ◽  
pp. 1440007
Author(s):  
YU-CHEN CHENG ◽  
SHENG-FONG LIN ◽  
YUAN-YING CHANG ◽  
CHI-FANG CHEN ◽  
CHEN-FAR HUNG ◽  
...  
Keyword(s):  
Impulsive Noise ◽  
Wind Farms ◽  
Propagation Model ◽  
Offshore Wind ◽  
Western Coast ◽  
Underwater Sound ◽  
Underwater Noise ◽  
Source Modeling ◽  
Noise Impact ◽  
Impact Region

Offshore wind farms are the main project on Taiwan's western coast. Since the underwater noise generated by piling poses a threat to marine mammals, the issue of the detrimental impact of noise on Sousa Chinensis has drawn considerable attention. To avoid behavioral disturbances and injury from pile driving noise, we propose the Underwater Noise Impact Region Alert System (UNIRAS) to estimate the acoustic field at any depth and distance from the piling sources. The system can be illustrated as four components: environment databases, an acoustic propagation model, source modeling and alert region (AR) prediction. Inputs are derived from the Taiwan Coastal Ocean Nowcast/Forecast System (TCONFS), which generates underwater sound speed profiles with temporal and spatial variation, along with geoacoustic and bathymetry databases that are imported as environmental inputs. Adiabatic mode theory is used to simulate the piling noise propagation in shallow water and the impulsive noise emanating from the source is evaluated via the finite element method. With the auditory threshold of cetacean being set as the criterion level, the system can demonstrate the modeling outputs and predict the noise impact region, and these results are useful for planning how to station the guard boats to prevent dolphins from entering the noise impact region.

scholarly journals Measurement of Underwater Acoustic Energy Radiated by Single Raindrops

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2687
Author(s):  
Shu Liu ◽  
Qi Li ◽  
Dajing Shang ◽  
Rui Tang ◽  
Qingming Zhang
Keyword(s):  
Ambient Noise ◽  
Sound Pressure ◽  
Tap Water ◽  
Acoustic Energy ◽  
Underwater Sound ◽  
Underwater Noise ◽  
Energy Characteristics ◽  
Sound Energy ◽  
Dipole Radiation ◽  
Series Of Experiments

Underwater noise produced by rainfall is an important component of underwater ambient noise. For example, the existence of rainfall noise causes strong disturbances to sonar performance. The underwater noise produced by a single raindrop is the basis of rainfall noise. Therefore, it is necessary to study the associated underwater noise when drops strike the water surface. Previous research focused primarily on the sound pressure and frequency spectrum of underwater noise from single raindrops, but the study on its sound energy is insufficient. The purpose of this paper is to propose a method for predicting the acoustic energy generated by raindrops of any diameter. Here, a formula was derived to calculate the underwater sound energy radiated by single raindrops based on a dipole radiation pattern. A series of experiments were conducted to measure the underwater sound energy in a 15 m × 9 m × 6 m reverberation tank filled with tap water. The analysis of the acoustic energy characteristics and conversion efficiency from kinetic to acoustic energy helped develop the model to predict the average underwater sound energy radiated by single raindrops. Using this model, the total underwater sound energy of all raindrops during a rainfall event can be predicted based on the drop size distribution.

A REVIEW OF PRACTICAL METHODS FOR REDUCING UNDERWATER NOISE POLLUTION FROM LARGE COMMERCIAL VESSELS

2021 ◽  
Vol 154 (A2) ◽  
Author(s):  
R C Leaper ◽  
M R Renilson
Keyword(s):  
Noise Pollution ◽  
Operating Conditions ◽  
Wake Flow ◽  
Underwater Noise ◽  
Data Set ◽  
Marine Life ◽  
Propeller Design ◽  
Widespread Agreement ◽  
Noise Measurements ◽  
Considerable Concern

Underwater noise pollution from shipping is of considerable concern for marine life, particularly due to the potential for raised ambient noise levels in the 10-300Hz frequency range to mask biological sounds. There is widespread agreement that reducing shipping noise is both necessary and feasible, and the International Maritime Organization is actively working on the issue. The main source of noise is associated with propeller cavitation, and measures to improve propeller design and wake flow may also reduce noise. It is likely that the noisiest 10% of ships generate the majority of the noise impact, and it may be possible to quieten these vessels through measures that also improve efficiency. However, an extensive data set of full scale noise measurements of ships under operating conditions is required to fully understand how different factors relate to noise output and how noise reduction can be achieved alongside energy saving measures.

Underwater Noise Due to Marine Life

1946 ◽  
Vol 18 (2) ◽  
pp. 446-449 ◽  
Author(s):  
Donald P. Loye ◽  
Don A. Proudfoot
Keyword(s):  
Underwater Noise ◽  
Marine Life

scholarly journals Violation of Marine Pollution Laws in Karachi Harbour Became an Environmental Challenge

2017 ◽  
Vol 5 (1) ◽  
pp. 66
Author(s):  
Muhammad Tahir
Keyword(s):  
Heavy Metals ◽  
Marine Environment ◽  
Pollution Control ◽  
Coastal Waters ◽  
Marine Pollution ◽  
Political Will ◽  
Marine Life ◽  
Standard Values ◽  
Marine Vessels ◽  
Environmental Challenge

This article appraises the Factors deteriorating marine environment due to violation of marine pollution laws in Pakistani waters. The environmental degradation of Pakistani waters especially in Karachi coast became a serious threat to the marine environment, marine life as well as human health and marine vessels since long for society. It is determined the level and the distribution pattern of various heavy metals in the coastal waters significantly higher than the standard values. Pollution created by a number of sources is the major contributing factor in this regard. Amongst all, the deteriorating environment in Pakistani waters warrants immediate corrective actions to control Marine Pollution in order to curtail further destruction by this menace. Many steps at Governmental and private level have been initiated however, improvement is a dream. It is rightly to mention that there is no dearth of legislation on the pollution control but implementation of the same by all the concerned agencies and cooperation by public in true letter and spirit is a dream. The prevailing environment cannot be improved without effective enforcement of existing laws in its true perspective by removing all obstacles and difficulties with creating political will of society.

scholarly journals Measurement of small vessel machinery vibration induced acoustic signature levels

2019 ◽  
Vol 16 (2) ◽  
pp. 87-98 ◽  
Author(s):  
GVV Pavan Kumar ◽  
V V S Prasad ◽  
B H Nagesh
Keyword(s):  
Pressure Fluctuations ◽  
Response Spectra ◽  
Underwater Sound ◽  
Underwater Noise ◽  
Noise Levels ◽  
Small Vessels ◽  
Performance Point ◽  
Engine Room ◽  
Airborne Noise ◽  
Main Engine

Ship vibrations, airborne and underwater noise levels have always been a challenging topic from a performance point of view in ship design, building and operation. The measurement shall help in monitoring the self-noise and the technical state of their machinery mechanism. The vibration levels on the main engine and auxiliary Genset foundation, airborne noise levels of the engine room and underwater self-noise levels of a small mechanized fishing trawler was measured at the jetty in idling condition.  The vibration levels on the foundation measured the average value of 0.207 mm/s for the main engine and 1.36 mm/s for auxiliary Genset. The airborne noise levels measured 99 dB (A) in the engine room. The peak underwater sound pressure levels measured 162 dB re 1µPa. The response spectra indicate the peak vibration and noise levels in the lower frequency region <1.2 kHz. The machinery excitation forces transferred to the hull surface as pressure fluctuations which generated the airborne and underwater noise levels. Though the measurement limited to jetty conditions, detailed analysis can be useful for detection, classification, and tracking of small vessels.

scholarly journals A Chebyshev-Tau spectral method for normal modes of underwater sound propagation with a layered marine environment

2021 ◽  
Vol 492 ◽  
pp. 115784
Author(s):  
Houwang Tu ◽  
Yongxian Wang ◽  
Qiang Lan ◽  
Wei Liu ◽  
Wenbin Xiao ◽  
...  
Keyword(s):  
Spectral Method ◽  
Marine Environment ◽  
Sound Propagation ◽  
Normal Modes ◽  
Underwater Sound

Methodology for environmental impact assessment of underwater noise on marine mammals

2011 ◽  
Vol 51 (1) ◽  
pp. 467
Author(s):  
Dick Petersen ◽  
Antoine David ◽  
Darren Jurevicius
Keyword(s):  
Oil And Gas ◽  
Sound Propagation ◽  
Underwater Acoustics ◽  
Oil And Gas Industry ◽  
Marine Species ◽  
Marine Ecology ◽  
Underwater Sound ◽  
Underwater Noise ◽  
Mammal Species ◽  
Marine Fauna

The oil and gas industry uses some exploration and production technologies that produce high levels of underwater sound, such as seismic surveys, underwater blasting for demolition and construction, and offshore piling. These underwater noise sources have the potential to impact marine species, which are usually reliant on sound instead of light as their primary sense for communication and sensing their environment. Regulatory interest in minimising the impacts of underwater noise on marine fauna is increasing. This paper presents a methodology for assessing these environmental impacts, with particular focus on cetaceans (whales and dolphins) and pinnipeds (seals and sea lions), although it can easily be adapted to other marine mammal species and fishes. It requires input from a variety of fields, such as: underwater acoustics for sound propagation modelling and source noise characterisation; marine bio-acoustics for determining the effects of sound on marine species’ hearing and communication; and marine ecology for identifying the marine species that may be affected and assessing the biological importance of noise-affected marine areas. These inputs are used in a risk assessment to assess the likely impacts of underwater noise on marine species, which is a collaborative effort by specialists in the fields of underwater acoustics, marine bio-acoustics and marine ecology.

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