Appendices 5-13 - Nautilus Cares - Nautilus Minerals

Depth (m)
0
500
1000
1500
2000
2500
1480 1490 1500 1510 1520 1530 1540 1550
Compressional sound speed (m/s)
Figure 6. Water column sound speed profile used for propagation modelling.
2.3! Received level calculations
Received levels were calculated for each bathymetry track as follows:
* The propagation model was run to obtain transmission loss as a function of range
and depth for frequencies spaced at 1/3 octave intervals from 8 Hz to 1 kHz.
* The source level at each of these frequencies was obtained by integrating the
source spectrum over a 1/3 octave frequency band centred on the desired
frequency.
* The source level and transmission loss were then combined to compute the
received level as a function of range and depth for a grid of points covering the
length of the propagation track (12 km) to a depth of 2000 m. Range and depth
increments were both 50 m.
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