Characterizing the ocean with acoustic waves: from seismic oceanography imaging to inversion

Seismic oceanography can be used to provide oceanographic insights about ocean processes happening simultaneously at large- and small-scales. We illustrate the potential of seismic oceanography data, by processing and inverting a set of three parallel two-dimensional multichannel seismic reflection profiles acquired in the Madeira Abyssal Plain during June 2006. The seismic sections were processed to image in detail the fine scale structure of the water column close to the sea surface. A similar processing sequence was applied to the three sections aiming to preserve, as much as possible, the relative seismic amplitudes of the data and enhance the shallow structure of the water column by effectively suppressing the direct arrival. The final processed seismic oceanography sections show several features of interest, comprising eddies at the expected Mediterranean Outflow Water depths, steeply dipping reflectors, which indicate the possible presence of frontal activity or secondary dipping eddy structures, and strong horizontal reflections between intermediate water masses suggestive of double diffuse processes. Then, we applied an iterative geostatistical seismic oceanography inversion methodology to predict the spatial distribution of temperature and salinity along each section. For the inversion we combined information about the ocean temperature and salinity from different sources. After the inversion, the predicted temperature are salinity models were interpolated with geostatistical simulation techniques to provide information regarding the region in between sections.