The Next Decade of Seismic Oceanography: Possibilities, Challenges and Solutions

Abstract

Seismic reflection profiling of thermohaline structure has the potential to transform our understanding of oceanic mixing and circulation. This profiling, which is known as seismic oceanography, yields acoustic images that extend from the sea surface to the sea bed and which span horizontal distances of hundreds of kilometers. Changes in temperature and salinity are detected in two, and sometimes three, dimensions at spatial resolutions of ~O(10) m. Due to its unique combination of extensive coverage and high spatial resolution, seismic oceanography is ideally placed to characterize the processes that sustain oceanic circulation by transferring energy between basin-scale currents and turbulent flow. To date, more than one hundred research papers have exploited seismic oceanographic data to gain insight into phenomena as varied as eddy formation, internal waves, and turbulent mixing. However, despite its promise, seismic oceanography suffers from three practical disadvantages that have slowed its development into a widely accepted tool. First, acquisition of high-quality data is expensive and logistically challenging. Second, it has proven difficult to obtain independent observational constraints that can be used to benchmark seismic oceanographic results. Third, computational workflows have not been standardized and made widely available. In addition to these practical challenges, the field has struggled to identify pressing scientific questions that it can systematically address. It thus remains a curiosity to many oceanographers. We suggest ways in which the practical challenges can be addressed through development of shared resources, and outline how these resources can be used to tackle important problems in physical oceanography. With this collaborative approach, seismic oceanography can become a key member of the next generation of methods for observing the ocean.

Introductory Chapter: General Overview on Oceanography

“…One of the main techniques used in geological oceanography is seismic, which involves the emission of sound waves that are reflected from different underground layers, allowing scientists to obtain a three-dimensional image of the marine subsoil. Other techniques include taking sediment samples, using sonar to map the seafloor, and conducting underwater drilling [23].…”

Unlocking A Global Ocean Mixing Dataset: toward Standardization of Seismic-derived Ocean Mixing Rates

“…The choice of reflection length clearly influences how well turbulence is represented by slope spectra, an issue that remains unresolved and as such more quantitative analysis is needed in the future. Ideally, with technical advancement, spectra could be computed directly from seismic-inverted sections of temperature and salinity, avoiding the need to track reflections (Dickinson and Gunn, 2022).…”

“…Because stacking is essential in producing images of thermohaline fine structures, ML denoising on pre-stack data might be challenging due to weaker reflection amplitudes, which could potentially be misinterpreted as noise by ML algorithms. In any case, with proper tools to ensure the spectra integrity, seismic oceanography can provide a global inventory of oceanic horizontal-wavenumber spectra which could greatly improve our understanding of energy cascade across different length scales and thereby building better parametrizations for climate models (Dickinson and Gunn, 2022).…”

“…1A) (Holbrook et al, 2003). The current development of SO and its distinctive features compared to other observations have been comprehensively reviewed by Dickinson and Gunn (2022). SO has been used to map the spatial distribution of turbulent mixing in diverse environments, including continental margins (Falder et al, 2016;Fortin et al, 2016;Dickinson et al, 2017); ocean ridges (Tang et al, 2021;Tang et al, 2022), oceanic fronts and mesoscale eddies (Tang et al, 2020;Gunn et al, 2021), open ocean interior (Wei et al, 2022) and the Arctic Ocean (Yang et al, 2023).…”

Research on the fluid dynamics interaction between submarine sand waves and seawater by seismic oceanography

“…Seismic oceanography (Holbrook et al, 2003) has been applied to study various oceanographic phenomena, including fronts (Holbrook et al, 2003;Tsuji et al, 2005), water mass boundaries (Nandi et al, 2004), mesoscale eddies (Biescas et al, 2008;Meńesguen et al, 2009;Song et al, 2009;Pinheiro et al, 2010;Quentel et al, 2010;Tang et al, 2014), internal waves (Holbrook and Fer, 2005;Krahmann et al, 2008;Song et al, 2009;Song et al, 2021b), submesoscale processes (Sallares et al, 2016;Tang et al, 2020;Yang et al, 2021), and seafloor processes (Vsemironva et al, 2012;Chen et al, 2016;Chen et al, 2017;Chen et al, 2018;Geng et al, 2019;Yin et al, 2021). More recently, seismic reflection studies have now been used to look at the evolution of marine processes over time (Dickinson et al, 2020;Gunn et al, 2020;Zou et al, 2021;Dickinson and Gunn, 2022). Seismic oceanography has been used to preliminarily analyze some significant images of fluid-solid interactions near the seafloor, such as submarine sand waves induced hair-like reflection configuration (Chen et al, 2016).…”