SOFTWARE SUPPORT FOR INVESTIGATION OF NATURAL METHANE SEEPS BY HYDROACOUSTIC METHOD
Keywords:
gas bubble streams, acoustic method, echo sounder SIMRAD EK-500, specialized softwareAbstract
The natural gas seepages from the sea floor are commonly recognized acoustically by the flare shaped acoustic images, spreading vertically through the water column. These acoustic images, which are made up of echoes from numerous gas bubbles, convey a lot of information about features of individual bubbles and bubbling vents in whole. To study the ecological role of methane gas bubble streams it is important to obtain such data, especially: the area of a venting site; total number of bubbles, released per a time period; size spectrum and rise velocity of bubbles at different depths through the water column. An approach based on the use of calibrated echo-sounder, digital data recording and processing techniques can provide adequate quantitative analysis of the backscattering signal. This paper describes the concepts for processing of acoustic information and particular realization of these concepts, adapted to the investigation of gas bubble streams with the use of scientific echo sounder SIMRAD EK-500 as a hydroacoustic instrument. The developed software includes a number of specialized procedures expanding performance capabilities of an acoustic method for the study of natural methane seepages. The work of these procedures is demonstrated by examples, obtained during a number of scientific cruises on board the RV “Professor Vodyanitsky”.
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