Cyclones and Anticyclones in Seismic Imaging

• Published in: Journal of Physical Oceanography
• Main Authors: Barbosa Aguiar, A. C., Menesguen, Claire, Le Gentil, Sylvie, Schopp, Richard, Carton, Xavier
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Meteorological Soc 2015
• Subjects: Geographic location/entity; North Atlantic Ocean; Circulation/ Dynamics; Small scale processes; Atm/Ocean Structure/ Phenomena; Eddies; Vortices; Observational techniques and algorithms; Acoustic measurements/effects; Models and modeling; Primitive equations model; North Atlantic; Northeast Atlantic
• Online Access: https://archimer.ifremer.fr/doc/00281/39190/37746.pdf; https://doi.org/10.1175/JPO-D-15-0066.1; https://archimer.ifremer.fr/doc/00281/39190/

Nearly all the subsurface eddies detected in seismic imaging of sections in the northeast Atlantic have been assumed to be anticyclones containing Mediterranean Water (MW). Fewer MW cyclones have been observed and studied. In this study, the work of previous numerical studies is extended to investigate some characteristics of layering surrounding MW cyclones, using a primitive equation model with equal diffusivities for salinity and temperature to suppress the effects of double diffusion. It is shown that, after a stable state is reached, both anticyclones and cyclones display similar patterns of layering: stacked thin layers of high acoustic reflectivity located above and below the core of each vortex, which do not match isopycnals. The authors conclude that it should not be possible to distinguish between MW cyclones and anticyclones based on their signature in seismic imaging alone. Complementary information is needed to determine the sense of rotation.