(2) Acoustical scientific goals Underwater sound propagation can be significantly affected by physical oceanographic processes and marine geological features, both of which can be found in a submarine canyon area, so canyon acoustics has been one of our research directions in the acoustics group at WHOI. The attached figure shows a numerical model prediction of the 3-D acoustic focusing effect in a submarine canyon (Lin et al., 2015). One of the scientific goals of our test in the Alvin Canyon is to verify this 3D focusing effect. Furthermore, we would like to study the temporal variability of the sound field caused by the shelfbreak and canyon flow dynamics. Figure 1. Three-dimensional and 2-D numerical models of sound propagation in the North Mien-Hua Canyon. A 0-dB point source transmitting 600-Hz CW sound is considered. The source depth is 61 m. Cylindrical spreading loss is factored out to reduce the dynamic range of sound intensity in the plot. The intensified spot shown in the 3D solution (b) is caused by the 3D acoustic focusing effect. Reference: Y.-T. Lin, T.F. Duda, C. Emerson, G.G. Gawarkiewicz, A.E. Newhall, B. Calder, J.F. Lynch, P. Abbot, Y.-J. Yang and S. Jan, “Experimental and numerical studies of sound propagation over a submarine canyon northeast of Taiwan,” IEEE J. Ocean. Eng., vol. 40, pp. 237-249 (2015). (3) Proposed acoustics tasks Equipment "Deep Sound" Acoustic receiver platform AMAR Hydrophone VLA SHRU Hydrophone VLA Shipboard Sound Sources (400 and 900Hz) PO Sensors (a) First deploy two hydrophone VLA's for long term recording at the head of the canyon. (b) at each night, we will deploy the Deep Sound platform for short term recording. (c) Shipboard source transmission (400 Hz and 900 Hz; M-Sequence, LFM and tonal signals) -- single station transmissions for 6+ hours with Yo-Yo CTD -- multiple station transmission to form a couple of transects along and across the canyon (each station for 30 min with Yo-Yo CTD) -- the source will be navigated by the USBL HiPAP system for precise positions. (d) Shipboard ADCP, sub-bottom profiler and multibeam sonar will be ON.
(2) Acoustical scientific goals Underwater sound propagation can be significantly affected by physical oceanographic processes and marine geological features, both of which can be found in a submarine canyon area, so canyon acoustics has been one of our research directions in the acoustics group at WHOI. The attached figure shows a numerical model prediction of the 3-D acoustic focusing effect in a submarine canyon (Lin et al., 2015). One of the scientific goals of our test in the Alvin Canyon is to verify this 3D focusing effect. Furthermore, we would like to study the temporal variability of the sound field caused by the shelfbreak and canyon flow dynamics. Figure 1. Three-dimensional and 2-D numerical models of sound propagation in the North Mien-Hua Canyon. A 0-dB point source transmitting 600-Hz CW sound is considered. The source depth is 61 m. Cylindrical spreading loss is factored out to reduce the dynamic range of sound intensity in the plot. The intensified spot shown in the 3D solution (b) is caused by the 3D acoustic focusing effect. Reference: Y.-T. Lin, T.F. Duda, C. Emerson, G.G. Gawarkiewicz, A.E. Newhall, B. Calder, J.F. Lynch, P. Abbot, Y.-J. Yang and S. Jan, “Experimental and numerical studies of sound propagation over a submarine canyon northeast of Taiwan,” IEEE J. Ocean. Eng., vol. 40, pp. 237-249 (2015). (3) Proposed acoustics tasks Equipment "Deep Sound" Acoustic receiver platform AMAR Hydrophone VLA SHRU Hydrophone VLA Shipboard Sound Sources (400 and 900Hz) PO Sensors (a) First deploy two hydrophone VLA's for long term recording at the head of the canyon. (b) at each night, we will deploy the Deep Sound platform for short term recording. (c) Shipboard source transmission (400 Hz and 900 Hz; M-Sequence, LFM and tonal signals) -- single station transmissions for 6+ hours with Yo-Yo CTD -- multiple station transmission to form a couple of transects along and across the canyon (each station for 30 min with Yo-Yo CTD) -- the source will be navigated by the USBL HiPAP system for precise positions. (d) Shipboard ADCP, sub-bottom profiler and multibeam sonar will be ON.
1458316591200_9722_SVC_III_Acoustic_Test_Plan_Draft.docx