modellizzazione in mar ionio - agenda (indico)...e-mail: rosario.grammauta@iamc.cnr.it...
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Rosario Grammauta1, Salvatore Viola2,
(1) IAMC-CNR UO Granitola, Campobello di Mazara (TP), Italy,
(2) INFN - Laboratori Nazionali del Sud, Catania,,Italy
e-mail: rosario.grammauta@iamc.cnr.it
Modellizzazione in Mar Ionio
1
Summary
2
Spatial distribution of the acoustic noise levels caused by shipping traffic in two areas of the
strait of Sicily.
Area of Capo Granitola
Summary
The first study area, the Gulf of Catania, isaffected by intense shipping traffic due to thepresence of three important harbors: touristic,commercial and military.
Calculation of the vessels’ position on a grid having mesh size 2000m x 2000m, with a time resolution of 30 minutes.
Study areaMin Longitude: 15.0°Max Longitude: 15.9°Min Latitude: 36.8°Max Latitude: 37.8°
Analyzed AIS dataTime period: November 2012 – November 2013 Number of vessels: 3621Total hour vessels: 43355
Cumulative minutes of ship traffic calculated in a 2000m x 2000m grid from AIS data
101
0
102
103
104
105
LAT
[deg
]
LON [deg]
Min
ute
Gulf ofCatania
Summary
The second area, instead, is the Area of
Capo Granitola where the massive
maritime traffic is attributable to the Strait
of Sicily.
Calculation of the vessels’ position on a grid having mesh size 2000m x 2000m, with a time resolution of 30 minutes.
101
0
102
103
104
105
Min
ute
Cumulative minutes of ship traffic calculated in a 2000m x 2000m grid from AIS data
Study areaMin Longitude: 12.0°Max Longitude: 13.6°Min Latitude: 36.6°Max Latitude: 37.8°
Analyzed AIS dataTime period: November 2012 – November 2013 Number of vessels: 10329Total hour vessels: 156550
LAT
[deg
]
LON [deg]
Area of Capo Granitola
Area of Capo Granitola
Modelling underwater noise from AIS data
The acoustic noise induced by ship traffic in the Gulf of Catania has been estimated with afast custom-written MATLAB script from the data collected by the AIS receiver installed atthe INFN-LNS.
Script steps:
1. Calculation of the vessels’ position on a grid having mesh size 100m x 100m, with atime resolution of 10 minutes.
2. Estimation of the source spectral density for each vessel according to the ResearchAmbient Noise Directionality model RANDI 3.1 (depending on speed, length of thevessel).
3. Evaluation of the effects of the surface-dipole interference on radiated sound power.
4. Application of an easy geometric spreading model accounting spherical spreading tothe maximum water depth along the modeling radius, and cylindrical spreading forthe remainder of the radius .
5. Computation of the frequency-dependent absorption
Modelling underwater noise from AIS data
• Calculation of the vessels’ position on a grid having mesh size 100m x 100m, with a time resolution of 10 minutes.
Study areaMin Longitude: 15°Max Longitude: 16°Min Latitude: 36.8°Max Latitude: 37.8°
Analyzed AIS dataTime period: 1st October, 2012 to 28th February, 2013
Cumulative minutes of ship traffic calculated in a 100m x 100m grid
Gulf of Capo Catania
Cu
mu
lative Min
ute
The pink triangle indicates the location of the
NEMO-SN1 observatory (37.5477 N, 15.3975 E, depth
2100 m).
Modelling underwater noise from AIS data
• Estimation of the source spectral density for each vesselaccording to the Research Ambient Noise Directionalitymodel RANDI 3.1 (depending on speed, length of thevessel).
Breeding, J. E., Pflug, L. A., Bradley, M., Herbert, M., and Wooten, M. (1994). RANDI 3.1 User's Guide: Naval Research Laboratory.
Breeding, J. E., Pflug, L. A., Bradley, M., Walrod, M. H., and McBride, W. (1996). Research Ambient Noise Directionality (RANDI) 3.1
Physics Description: Planning System Incorporated.
In this formula, cV and cLare power-law coefficients for speed and length (taken to be 6and 2, respectively), v0 is the reference speed (12 kt), l0 is the reference length (300 ft),Ls0(f) is a mean reference spectrum, and g(f,l) is an additional length--‐dependentcorrection to the Ross model (Breeding et al., 1996).
Modelling underwater noise from AIS data
• Evaluation of the effects of the surface-dipole interferenceon radiated sound power.
To account for the effect of surface-dipole interference on radiated sound power, sourcelevels at wavelengths greater than four times the source depth were attenuated accordingto the relation given by Brekhovskikh and Lysanov
Modelling underwater noise from AIS data
9
• Application of an easy geometric spreading modelaccounting spherical spreading to the maximum waterdepth along the modeling radius, and cylindrical spreadingfor the remainder of the radius .
Modelling underwater noise from AIS data
• Computation of the frequency-dependent absorption
due to the relaxation of boric acid
B(OH3) and magnesium sulphate
MgSO4 molecules, and the shear &
bulk viscosity of pure water
TL = αR
Validation of Model
• NEMO-SN1 Observatory
• Long-term background noise measurements in the Gulf of Catania
• Evaluation of the background acoustic noise from ship traffic
• Comparison between the AIS-derived noise levels and the real acoustic data
The NEMO-SN1 Observatory and the Catania node of EMSO
Low frequency
hydrophone
INFN – LNS shore lab
NEMO – SN1
NEMO - SN1 is the first-established node of EMSO (European Multidisciplinary SeafloorObservatory), one of the incoming European large-scale research infrastructure includedsince 2006 in the Roadmap of the ESFRI (European Strategy Forum on ResearchInfrastructures). http://www.emso-eu.org/
NEMO-SN1 seafloor observatory has been operating from June, 2012 to May, 2013 in the Western Ionian Sea (East Sicily, 37°30’ N – 15°06’ E), at about 2100 m water depth.
Up: geographic location of the NEMO – SN1 multidisciplinary observatory
Right: NEMO – SN1 operative underwater
3
NEMO-SN1 low-frequency hydrophone
4
Underwater acoustic noise in the Gulf of Catania was measured through a seismichydrophone, model SMID DT- 405D (10 Hz<f<1 KHz). Acoustic data were collected fromJune 2012 to May 2013, 24 hours per day, at a sampling frequency of 2 kHz, saved in 10min long files and stored at the INFN – LNS.
High Gain Channel (+60 dB)
Low Gain Channel (+30 dB)
Ch0=+60 dBCh1=+30 dB
DATA OUTDATA IN (CONTROL)
PPS – GPS (NMEA)
DIGITIZERPREAMP
About 4600010-min files stored
Distribution of the mean values of the PSD within each 10 min long recording (binning:1dB re 1 µPa2/Hz) for the whole NEMO-SN1 acoustic dataset (46040 recordings). PSD ofeach file computed using Welch's overlapped segment averaging estimator (window: 2048samples, overlap 50%). The gure also includes the curves of the 50th, 90th and 10thpercentiles of the mean values of the PSD calculated on the whole acoustic dataset.
Underwater background noise in the Gulf of Catania
46040 recordingsJune 2012 - May 2013
AIS data acquisition at the INFN-LNS laboratory
AIS data displayed in real time on a Google
map web page
INFN-LNS STORAGE
INFN – LNS CATANIA
The Automatic Identification System (AIS) is an automatic tracking system used by ships for identify and locate vessels. It gives information such as position, mmsi, speed and length.
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Comparison between AIS-derived and real acoustic data 1/3
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SPL within the 31.5 Hz, 63 Hz, 125 Hz and 250 Hz octave bands at the NEMO-SN1 location (redlines) was simulated with a time resolution of 10 minutes and it was compared with the SPLmeasured from NEMO-SN1 recordings (blue lines).A minimal background noise given by the smallest values of SPL obtained by the NEMO-SN1data was considered in the simulation. ___ NEMO-SN1 recordings
___ Simulation
Comparison between AIS-derived and real acoustic data 2/3
Distribution of the difference (in dB) between the estimated SPL (dB re 1 µPa) at the NEMO-SN1 location and the SPL measured from NEMO-SN1 recordings (calculated with a time resolution of 10 min) for the 63 Hz and 125 Hz centered octave bands.
Period between 1st October, 2012 and the 28thFebruary, 2013.
Comparison between AIS-derived and real acoustic data 3/3
Shipping noise evaluation at different depths
Estimated mean acoustic PSD at 100 Hz (dB re 1 µPa2/Hz) induced by the ship traffic in the study area for December 2012 at three different depths
Noise levels have been estimated at different frequencies and depths on a grid having meshsize 100m x 100m, with a time resolution of 10 minutes.
Mean PSD at 100 Hz Mean PSD at 100 Hz Mean PSD at 100 Hz
NEMO-SN1 NEMO-SN1 NEMO-SN1
Results
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Estimated mean acoustic PSD at 63 Hz (dB re 1 µPa2/Hz) induced by the ship traffic in the study area for all 2013 at 5m of depth.
Area of Capo Granitola
Area of Capo Granitola
Gulf of Catania
Results
15
Estimated mean acoustic PSD at 125 Hz (dB re 1 µPa2/Hz) induced by the ship traffic in the study area for all 2013 at 5m of depth.
Area of Capo Granitola
Area of Capo Granitola
Gulf of Catania
Results
90
95
100
105
110
115
Winter Spring Summer Autumn
dB
re
1 µ
Pa2
/Hz
Titolo asse
Comparison: Estimated, with Model, mean acoustic PSD at 63 Hz in the two areas of studio
Granitola 63 Hz Catania 63 Hz Mean 2013 Mean 2013
≈ 15 dB
Area of Capo Granitola
Gulf of Catania
Application of Model
source spectral density for each vessel
the intensity of the source is dependent on the speed of the ship
we use the model to predict what would happenif the ships would change its speed
decreasing the speed of the ships also decreasesthe intensity of the signal emitted by ships
106
107
108
109
110
111
112
113
Winter Spring Summer Autumn
dB
re
1 µ
Pa2
/Hz
Comparison mean acoustic PSD at 63 Hz Granitola (Year 2013)
Granitola 63 Hz 2013 Granitola 63 Hz reduced Mean 2013 reduced
Comparison acoustic PSD Granitola after changed speed ship
speed vesselsreduced by 10 %
≈ -3 dB
Area of Capo Granitola
Area of Capo Granitola
Comparison acoustic PSD Catania after changed speed ship
92
93
94
95
96
97
98
99
Winter Spring Summer Autumn
dB
re
1 µ
Pa2
/Hz
Comparison mean acoustic PSD Catania (Year 2013).
Catania 63 Hz Mean 2013 Catania 63 Hz reduced Mean 2013 reduced
speed vesselsreduced by 10 %
≈ -3 dB
Gulf of Catania Gulf of Catania
1
Management indication
90
95
100
105
110
115
Winter Spring Summer Autumn
dB
re
1 µ
Pa2
/Hz
Estimated mean acoustic PSD at 63 Hz in the two areas for 2013
Granitola 63 Hz Catania 63 Hz Mean 2013 Mean 2013 marine strategy
Gulf of Catania
Marine Strategy
≈12 dB
Area of Capo Granitola
Management indication
90
95
100
105
110
115
Winter Spring Summer Autumn
dB
re
1 µ
Pa2
/Hz
Hypothesized mean acoustic PSD at 63 Hz in the two areas for 2013
marine strategy Granitola 63 Hz Mean 2013 Catania 63 Hz Mean 2013
Area of Capo Granitola
≈ 8 dB
the speed of the ships is decreased by 10 %
Gulf of Catania
Marine Strategy
Management indication
If speed vesselsreduced by 10 %Area of
Capo GranitolaArea of
Capo Granitola
If speed
vessels
reduced by 20 %
Area of Capo Granitola
Area in the threshold of the Marine Strategy
(dB re 1 µPa2/Hz)
Conclusion and Future
• The model is a useful tool to evaluate the spatial distributions of
induced noise from vessel traffic. It is able to generate real-timemaps of noise using exclusively of AIS data;
• The model can be a useful tool for marine traffic control and for
establish new mitigation rules in order to reduce the marine
noise (Europea Marine Strategy).
• Improve the model in shallow water
• Improve the model by adding information about the tonnage and
draft of the ships;
• Improve the validation of the model increasing the data
collection point (Artic, Antartic, etc).
FUTURE
CONCLUSION
NOISE MAP PROJECT
Thanks for yourattention
1
Suitability of five commonly used propagation models for different water depths and frequencies
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