FN Archimer Export Format
PT J
TI Acoustic monitoring of gas emissions from the seafloor. Part I: quantifying the volumetric flow of bubbles
BT 
AF LEBLOND, Isabelle
   SCALABRIN, Carla
   BERGER, Laurent
AS 1:1;2:1;3:1;
FF 1:;2:PDG-REM-GM-LGG;3:PDG-IMN-NSE-AS;
C1 IFREMER, Plouzane, France.
C2 IFREMER, FRANCE
SI BREST
SE PDG-REM-GM-LGG
   PDG-IMN-NSE-AS
IN WOS Ifremer jusqu'en 2018
IF 1.264
TC 19
UR https://archimer.ifremer.fr/doc/00192/30336/29094.pdf
LA English
DT Article
DE ;Seafloor observatory;Water column acoustics;Forward and inverse modeling;Fisheries echosounders;Acoustic backscattering;Gas emissions;Bubbles;Water tank experiments
AB Three decades of continuous ocean exploration have led us to identify subsurface fluid related processes as a key phenomenon in marine earth science research. The number of seep areas located on the seafloor has been constantly increasing with the use of multi-scale imagery techniques. Due to recent advances in transducer technology and computer processing, multibeam echosounders are now commonly used to detect submarine gas seeps escaping from the seafloor into the water column. A growing number of en-route surveys shows that sites of gas emissions escaping from the seafloor are much more numerous than previously thought. Estimating the temporal variability of the gas flow rate and volumes escaping from the seafloor has thus become a challenge of relevant interest which could be addressed by sea-floor continuous acoustic monitoring. Here, we investigate the feasibility of estimating the volumetric flow rates of gas emissions from horizontal backscattered acoustic signals. Different models based on the acoustic backscattering theory of bubbles are presented. The forward volume backscattering strength and the inversion volumetric flow rate solutions were validated with acoustic measurements from artificial gas flow rates generated in controlled sea-water tank experiments. A sensitivity analysis was carried out to investigate the behavior of the 120-kHz forward solution with respect to model input parameters (horizontal distance between transducer and bubble stream, bubble size distribution and ascent rate). The most sensitive parameter was found to be the distance of the bubble stream which can affect the volume backscattering strength by 20 dB within the horizontal range of 0–200 m. Results were used to derive the detection probability of a bubble stream for a given volume backscattering strength threshold according to different bubble flow rates and horizontal distance.
PY 2014
PD SEP
SO Marine Geophysical Research
SN 0025-3235
PU Springer
VL 35
IS 3
UT 000342214300003
BP 191
EP 210
DI 10.1007/s11001-014-9223-y
ID 30336
ER

EF