Ocean convergence and the dispersion of flotsam

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Non
Statut de publication : Publié
Année de publication : 2018
Auteurs (19) : D'ASARO Eric SHCHERBINA A,y KLYMAK Jody,m MOLEMAKER J NOVELLI G GUIGAND C HAZA Angelique HAUS B,k RYAN E,h JACOBS G,a HUNTLEY H,s LAXAGUE N,j,m CHEN Sue JUDT F MCWILLIAMS J,c BARKAN R KIRWAN A,d POJE A,c ÖZGÖKMEN Tamay,m
Revue scientifique : Proceedings of the National Academy of Sciences of the United States of America
Volume : 115
Fascicule : 6
Pages : 1162-1167
DOI : 10.1073/pnas.1718453115
URL : -
Abstract : Floating oil, plastics, and marine organisms are continually redistributed by ocean surface currents. Prediction of their resulting distribution on the surface is a fundamental, long-standing, and practically important problem. The dominant paradigm is dispersion within the dynamical context of a nondivergent flow: objects initially close together will on average spread apart but the area of surface patches of material does not change. Although this paradigm is likely valid at mesoscales, larger than 100 km in horizontal scale, recent theoretical studies of submesoscales (less than similar to 10 km) predict strong surface convergences and downwelling associated with horizontal density fronts and cyclonic vortices. Here we show that such structures can dramatically concentrate floating material. More than half of an array of similar to 200 surface drifters covering similar to 20 x 20 km(2) converged into a 60 x 60 m region within a week, a factor of more than 105 decrease in area, before slowly dispersing. As predicted, the convergence occurred at density fronts and with cyclonic vorticity. A zipperlike structure may play an important role. Cyclonic vorticity and vertical velocity reached 0.001 s(-1) and 0.01 ms(-1), respectively, which is much larger than usually inferred. This suggests a paradigm in which nearby objects form submesoscale clusters, and these clusters then spread apart. Together, these effects set both the overall extent and the finescale texture of a patch of floating material. Material concentrated at submesoscale convergences can create unique communities of organisms, amplify impacts of toxic material, and create opportunities to more efficiently recover such material.
Mots-clés : BALTIC SEA; BLOOMS; dispersion; DYNAMICS; eddy; FRONT; GULF; MESOSCALE; ocean; STATISTICS; submesoscale; SUBMESOSCALE; vertical velocity
Commentaire : Times Cited in Web of Science Core Collection: 114
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Citation :
D'Asaro E, Shcherbina AY, Klymak JM, Molemaker J, Novelli G, Guigand C, Haza A, Haus BK, Ryan EH, Jacobs GA, Huntley HS, Laxague NJM, Chen S, Judt F, McWilliams JC, Barkan R, Kirwan AD, Poje AC, Özgökmen TM (2018) Ocean convergence and the dispersion of flotsam. Proc Natl Acad Sci U S A 115: 1162-1167 | doi: 10.1073/pnas.1718453115