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Significant independent variables with p-values less than 0.05, meaning that there was a more than 95 % probability that these variables were related to the dependent variable Leq,125Hz. The grey fields indicate insignificant independent variables with p-values greater than 0.05. The abbreviation n.a. means not applicable.
p-values
From 13.02.2015 to 05.05.2015
From 26.09.2015 to 31.12.2015
From 18.08.2016 to 01.11.2016
From 06.07.2017 to 07.08.2017
From 18.08.2018 to 31.12.2018
p (vv)
0.000
0.000
0.000
0.000
0.000
p (hp)
0.019
0.509
0.111
0.867
0.599
p (ρL,2NM)
0.097
0.022
0.000
0.033
0.000
p (ρL,5NM)
0.000
0.000
0.000
0.215
0.002
p (ρL,Tireste)
0.001
0.000
0.000
0.033
0.000
p (ρL,Venice)
0.256
0.110
0.036
0.000
0.000
p (dredg. act.)
n.a.
0.000
n.a.
n.a.
n.a.
p (clean. act.)
n.a.
n.a.
0.021
n.a.
n.a.
Examples of underwater noise levels related mainly to the ship traffic in the global seas and oceans.
Location, depth of the hydrophone and depth of the sea water
Year of study
Underwater noise levels at different frequencies
Location, depth of the hydrophone and depth of the sea water
Year of study
Underwater noise levels at different frequencies
Scotian Shelf, Canada, hydrophone depth of 31 m and water depth of 79 m [3]
1972–1985
Winter average noise levels at zero wind speed [3]:30 Hz: 90.8 dB re μPa2/Hz45 Hz: 90.5 dB re μPa2/Hz80 Hz: 87.9 dB re μPa2/Hz150 Hz: 81.9 dB re μPa2/Hz300 Hz: 74.1 dB re μPa2/Hz600 Hz: 64.4 dB re μPa2/Hz900 Hz: 64.3 dB re μPa2/Hz
Ramsey Sound, Pembrokeshire, West Wales, UK, hydrophone depth of 20 m and a water depth of 460 m [7]
2009
Sound pressure levels [7]:Between 5 Hz and 10 Hz:
92.6 dB re 1 μPa ± 3.9 dB re 1 μPa during spring
104.7 dB re 1 μPa ± 2.2 dB re 1 μPa during summer
Around 100 Hz:
85.9 dB re 1 μPa ± 2.4 dB re 1 μPa during spring
104.6 dB re 1 μPa ± 2.4 dB re 1 μPa during summer
India, shallow water, hydrophone depth of 5 m and water depth of 25 m [4]
2006
Average noise levels [4]:98 Hz: 130.3 dB re μPa/√Hz195 Hz: 128.6 dB re μPa/√Hz293 Hz: 127.3 dB re μPa/√Hz586 Hz: 127.6 dB re μPa/√Hz977 Hz: 127.4 dB re μPa/√Hz3027 Hz: 127.1 dB re μPa/√Hz4023 Hz: 127.1 dB re μPa/√Hz
Guanabara Bay, SE Brazil, hydrophone depth of 2 m and a water depth of 4 m [8]
2011–2012
The highest mean sound pressure level [8]):At 187 Hz:111.6 ± 9.0 dB re 1 μPaAt 15.89 kHz:76.2 ± 8.3 dB re 1 μPa
Indian Ocean, the lagoon of a coral atoll, hydrophone depth of 2–15 m and water depth of 50 m [5]
2005
Spectral maxima observed at 1 kHz and 7.5 kHz [5]:1,000 Hz: 72 dB re μPa/√Hz2,000 Hz: 65 dB re μPa/√Hz7,500 Hz: 80 dB re μPa/√Hz
Port of South Louisiana (H-3), Port of Houston (H-1), NE Gulf of Mexico, hydrophone depth from 250–1,370 m [9]
2010–2012
The highest values L01 (T = 1 h) at two sites (H-3 and H-1) nearest to high-shipping lanes [9] in LF band (10–500 Hz) were:130 dB re 1 μPa and 128 dB re 1 μPa, respectively(L01 = sound levels that were exceeded 1% of the time)
Northeast Pacific Ocean, SW of the San Nicolas Island, California, USA, hydrophone depth of 1,090–1,106 m [6]
1966 – 2006
Mean ambient noise levels:−30–50 Hz in 1964–1966: 73–75 dB re 1 Pa2/Hz−30–50 Hz in 2003–2004: 85 dB re 1 Pa2/Hz [6]
Celtic Sea, northern and southern North Sea in UK, hydrophone depth of 100 m and a water depth of 200 m [10]
2013–2014
Median noise levels for 1/3 octave bands from 63 Hz to 500 Hz [10]:81.5–95.5 dB re 1μPa
Regression equations in which the dependent variable Leq,125Hz was predicted by the significant independent variables (ρL,2NM, ρL,5NM, ρL,Trieste, ρL,Venice, dreadg. act., clean. act., vv and hp).
Significant independent variables with p-values lower than 0.05, meaning that there was a more than 95 % probability that these variables were related to the dependent variable Leq,63Hz. The grey fields indicate insignificant independent variables, with p-values greater than 0.05. The abbreviation n.a. means not applicable.
p-values
From 13.02.2015 to 05.05.2015
From 26.09.2015 to 31.12.2015
From 18.08.2016 to 01.11.2016
From 06.07.2017 to 07.08.2017
From 18.08.2018 to 31.12.2018
p (vv)
0.000
0.000
0.000
0.000
0.000
p (hp)
0.001
0.061
0.240
0.923
0.010
p (ρL,2NM)
0.005
0.691
0.048
0.003
0.036
p (ρL,5NM)
0.007
0.015
0.000
0.556
0.000
p (ρL,Trieste)
0.327
0.794
0.000
0.119
0.000
p (ρL,Venice)
0.037
0.087
0.023
0.342
0.000
p (dredg. act.)
n.a.
0.000
n.a.
n.a.
n.a.
p (clean. act.)
n.a.
n.a.
0.002
n.a.
n.a.
The Pearson correlation coefficients between the dependent variable (Leq,63Hz) and the independent variables (ρL,2NM, ρL,5NM, ρL,Trieste, ρL,Venice., dreadg. act., clean. act., vv and hp) in all measuring periods.
Pearson's correlation coefficient
From 13.02.2015 to 05.05.2015
From 26.09.2015 to 31.12.2015
From 18.08.2016 to 01.11.2016
From 06.07.2017 to 07.08.2017
From 18.08.2018 to 31.12.2018
r (vv)
0.58
0.51
0.54
0.39
0.35
r (hp)
−0.02
0.06
0.08
0.08
0.07
r (ρL,2NM)
0.13
−0.06
0.05
−0.04
0.05
r (ρL,5NM)
0.06
−0.06
0.02
0.09
0.08
r (ρL,Trieste)
−0.02
−0.03
0.08
0.12
0.12
r (ρL,Venice)
−0.10
−0.05
−0.05
0.01
−0.11
r (dredg. act.)
n.a.
0.31
n.a.
n.a.
n.a.
r (clean. act.)
n.a.
n.a.
−0.10
n.a.
n.a.
Multiple correlation coefficients (r) between dependent variables (Leq,63Hz and Leq,125Hz) and independent variables (ρL,2NM, ρL,5NM, ρL,Trieste, ρL,Venice, dreadg. act., clean. act., vv and hp) in all measuring periods.
Multiple correlation coefficients
From 13.02.2015 to 05.05.2015
From 26.09.2015 to 31.12.2015
From 18.08.2016 to 01.11.2016
From 06.07.2017 to 07.08.2017
From 18.08.2018 to 31.12.2018
r (Leq,63Hz)
0.59
0.55
0.57
0.40
0.40
r (Leq,125Hz)
0.41
0.21
0.59
0.29
0.23
The Pearson correlation coefficients between the dependent variable (Leq,125Hz) and the independent variables (ρL,2NM, ρL,5NM, ρL,Trieste, ρL,Venice, dreadg. act., clean. act., vv and hp) in all measuring periods.
Pearsons correlation coefficients
From 13.02.2015 to 05.05.2015
From 26.09.2015 to 31.12.2015
From 18.08.2016 to 01.11.2016
From 06.07.2017 to 07.08.2017
From 18.08.2018 to 31.12.2018
r (vv)
0.39
0.18
0.55
0.24
0.15
r (hp)
−0.02
0.01
0.09
0.04
0.02
r (ρL,2NM)
0.11
0.06
0.07
0.02
0.12
r (ρL,5NM)
0.05
0.05
−0.04
0.17
0.02
r (ρL,Trieste)
−0.02
0.02
0.01
0.18
0.04
r (ρL,Venice)
−0.08
−0.01
−0.09
−0.01
−0.10
r (dredg. act.)
n.a.
0.10
n.a.
n.a.
n.a.
r (clean. act.)
n.a.
n.a.
−0.10
n.a.
n.a.
Coefficients of determination (R2) between the dependent variables (Leq,63Hz and Leq,125Hz) and the independent variables (ρL,2NM, ρL,5NM, ρL,Trieste, ρL,Venice, dreadg. act., clean. act., vv and hp) in all measuring periods.
Coefficients of determination
From 13.02.2015 to 05.05.2015
From 26.09.2015 to 31.12.2015
From 18.08.2016 to 01.11.2016
From 06.07.2017 to 07.08.2017
From 18.08.2018 to 31.12.2018
R2(Leq,63Hz)
0.35
0.30
0.33
0.16
0.16
R2(Leq,125Hz)
0.17
0.05
0.34
0.09
0.05
Regression equations in which the dependent variable Leq,63Hz was predicted by the significant independent variables (ρL,2NM, ρL,5NM, ρL,Trieste, ρL,Venice, dreadg. act., clean. act., vv and hp).