Metropolis 1 Metropolis 2 Metropolis 3 Metropolis 4

Project Information

Underwater Sound Modelling:  Quonops will be used to produce an initial non-calibrated Noise Atlas, representative of seasonal and oceanographic situations for Irish waters. This will utilize data gathered in WP2 along with data on selected human activity scenarios (ship position, ship speed, power plant distribution and characteristics, offshore prospection activities, etc). To be calibrated, in-situ acoustic measurements need to be assimilated. For continuous sound (all types of ship), underwater sound modelling will be conducted in the area around representative shipping channels e.g. commercial ship traffic in arrival and departure at Dublin (Figure 1). For impulse sounds, underwater sound modelling will be conducted in 30’x30’ grid cells (Figure 3), identified as having significant activities (pile driving, seismic survey, Sonar) through data collection in WP2.

Lessons learned from this sound modelling about the structure of the noise will serve to define an enlightened strategy for in-situ measurement.

 

 

 

 

 

 

 

 

 

 

 

Figure 1 : At Dublin, example of principal commercial channel traffic

 

 

 

 

 

 

 

Figure 2 : Bathymetry of Irish waters, outline of EEZ in dashed line and 30’x30’ grid cells

 

In-Situ Monitoring Strategy: A pilot monitoring program is proposed in Cork Harbour, a busy shipping channel. A Passive Acoustic Monitor will be deployed for approximately 2 months. Data will be recorded to fully cover the frequency band required by the MSFD, and will be processed and analysed for noise content. Simultaneously, data on human maritime activities will be collected through, for example, AIS (Automated Identification System) messages, and impulse activities.

Underwater sound mapping by assimilation of in-situ measurements: The processed in-situ measurements will be used to calibrate the preliminary noise maps outlined above. Quiet-Oceans are currently finalising assimilation methods that can be used to calibrate the noise maps.

Risk Mapping: The combination of biological information, such as cetacean distribution with the noise maps outlined above, will produce an integrated picture with the potential to evaluate the accumulated sound energy experienced by species, and highlight potential behaviour changes due to sound pollution. Data on marine mammal distribution and behaviour will be integrated with noise maps from this WP. The use of noise thresholds will lead to a potential risk mapping of Irish waters. This would represent the first attempt to address the EU requirements for the introduction of sound energy that may adversely impact marine life.

 

Figure 3 : Example risk map towards Harbour Porpoises in the British Channel induced by a Pile Driving project in summer. The green area corresponds to a low acoustic risk, the yellow area to significant risk for behaviour changes of the animals, and the orange area to significant temporary physical damages on the animals.

 

Quonops© system: Quonops©combines real-time environmental data with real-time human generated wideband noise sources to produce the resulting 3D ocean noise fields. It has already been implemented to predict the changes induced by several offshore wind farm projects in France and has lead to improved management decisions.

The capacity to fuse real-time oceanographic parameters and real-time ship traffic data from the Automated Identification system (AIS) has also been already implemented within Quonops©’ Ocean Noise Prediction System as a patented innovation. This functionality has been applied to continuous monitoring of the three-dimensional and global ocean noise distribution in a roughly 96,000 km3 area centered around the Strait of Gibraltar and more recently, in the eastern and the western part of the British Channel. The analysis of the output of Quonops allows estimating:

  • The geographic distribution of noise (Figure 4),
  • The noise level statistics as a function of frequency (Figure 5),
  • The noise level probability function (Figure 6).

Figure 4: Illustration of low frequency Noise Pollution Mapping (snapshot from real-time data-flow) from commercial traffic, fishing, and pleasure activities in the British Channel, July 2010, produced by Quonops.

 

Figure 5: Noise percentiles (expressed in dB re. 1μPa) versus frequencies (octave bands) representative of the continuous sound in the British Channel, July 2010, produced by Quonops

 

Figure 6: Statistical representation of the noise in the octave centred at 256Hz. The y-axis represents the probability to measure a level higher than the corresponding acoustic level (x-axis). For example, in the British Channel (area displayed above), there is 90% chance to measure an averaged (blue curve) level of 90dB re. 1μPa2), with a variability of +/-20dB due to traffic and seasonal effects.