Reflections of low-frequency, broadband airgun signals from ocean water columns have
long been collected in modern marine seismic surveys. However, they were barely
examined because of their weak amplitude (following from low acoustic impedance contrast
in water columns) and the lack of application interests. Nevertheless, in the past decades, a
new cross-discipline “seismic oceanography” has developed the interest to use these water-
column reflection signals to image the ocean structures. Motivated by seismic oceanography …