Map of the Santa Barbara Channel. The northbound and southbound shipping lanes and 100 m bottom contours are shown. (HARP = black star, AIS station = white dot).
Received sound levels during 1-h passages of three different ship-types: (a) Container ship (MMSI 548719000). (b) Bulk carrier (MMSI 440223000). (c) Product tanker (MMSI 319768000). Figures are centered at CPA of the ship to the HARP. Negative CPA is bow aspect; whereas positive values are stern aspect. Top figure series shows the received levels as color (dB re 1 μPa2/Hz) during a 1-h window around the passage of the ships, using sequential 5 s spectral averages to form the long-term spectrogram (Hanning window, FFT length of 2000 samples and 80% overlap). Bottom figure series show measured RL above an estimate of background noise level. The corresponding distance traveled over that 1-h period is shown on the x axis on the bottom graphs; this scale is dependent on the speed of the ship.
Region specific PE transmission loss model. (a) Sound speed depth profile for water column and sediment during April 2009. (b) Sound propagation loss for 63 Hz one-octave band at depths of 510–570 m for different source depths (14 and 7 m). The ranges from the ships to the HARP are shaded in gray (wd = water depth at acoustic receiver in m).
Ship source levels for (a) container ships and vehicle carriers, (b) bulk carriers and open hatch cargos, and (c) three types of tankers. Top two series of figures show one-octave and 1/3 octave bands, with mean and standard errors. Bottom series shows the 1 Hz band levels.
Broadband ship source level versus speed for measured ships. Bubble color signifies ship-type. Bubble size represents the relative size of the ship, measured as GT from Table I.
Summary of commercial ship characteristics.
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