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Sheldon Bacon and Peter M. Saunders

–Scotland overflows can be observed before they enter the Labrador Sea is off Cape Farewell, the southern tip of Greenland. However the magnitude and variability of the transport of the deep western boundary current (DWBC), which contains the overflow waters east of Cape Farewell, is poorly understood. On the one hand, Clarke (1984) describes the derivation of the presently widely accepted value of 13 Sv (1 Sv = 1 × 10 6 m 3 s −1 ), based on a combination of a hydrographic section with a 60-day deployment of

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Y.-L. Chang and L.-Y. Oey

1. Introduction The Loop Current is the extension of the Yucatan Current and is the most prominent circulation feature in the Gulf of Mexico. Mainly confined in the upper 1000 m, the Loop Current has very strong speeds that can exceed 2 m s −1 (for a review and references, see Oey et al. 2005 ). Large warm-core rings (Loop Current eddies, 200–350 km wide and 500–1000 m deep) episodically separate from the Loop Current at time intervals that range from 3 to 18 months ( Sturges and Leben 2000

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Lars Umlauf, Lars Arneborg, Richard Hofmeister, and Hans Burchard

1. Introduction Submarine channels, canyons, and topographic corrugations have long been recognized for their potential importance in modifying the pathway, the dynamics, and the entrainment of dense bottom currents. Submarine channels, for example, have been identified as hot spots of gravity current entrainment at various locations ( Peters et al. 2005 ; Mauritzen et al. 2005 ; Baringer and Price 1997 ), and canyons and other small-scale corrugations are believed to play a key role for the

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N. Robb McDonald and E. R. Johnson

1. Introduction Circulation in the oceans is characterized by the presence of intense boundary currents. These vary from large-scale currents such as the Gulf Stream, deep western boundary currents, and the buoyancy-driven Leeuwin Current to smaller coastal flows driven by river outflow plumes under the influence of the Coriolis force. In many cases the boundaries along which these currents flow are not perfect barriers but instead are perforated by a series of gaps and straits. Many of the

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Hristina G. Hristova, Joseph Pedlosky, and Michael A. Spall

1. Introduction Radiating instability refers to an instability of the mean flow that propagates energy away from the source of instability. It can be contrasted with a trapped instability, the influence of which is confined mainly to the locally unstable region and has no impact on the far field. Previous studies have shown that parallel zonal eastward barotropic jets do not support radiating instabilities ( Talley 1983 ). For these currents, the perturbation energy stays trapped near the mean

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Vladimir Kudryavtsev, Victor Shrira, Vladimir Dulov, and Vladimir Malinovsky

1. Introduction The sensitivity of the ocean–atmosphere system to the processes at the ocean surface and in the few uppermost meters is well known: in particular, the first 2.5 m of water column have the same heat capacity as the entire atmosphere above; more than 40% of the solar radiation is absorbed in the first 10 m ( Gill 1982 ). However, despite persistent efforts of many research groups, the present understanding of links between wind waves, turbulence, and surface shear currents, as

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Jennifer Veitch, Pierrick Penven, and Frank Shillington

1. Introduction The Benguela system is the eastern boundary current system of the South Atlantic Ocean and is situated off the west coast of southern Africa (for its geographic location and a schematic of the salient features, refer to Fig. 1 ). As one of the world’s four major eastern boundary upwelling systems, the geographical location of the Benguela system is unique in that its southern boundary is coincident with the termination of both the African continent as well as the warm

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Volodymyr Zharkov and Doron Nof

. Under some conditions, the meanders grow exponentially, close upon themselves, and pinch off a closed loop with either cyclonic or anticyclonic circulation (depending on whether the meander is convex or concave, looking northward). Note that by “instability,” we refer to the classical definition, that is, the breakup of a known steady solution , not a mere transfer of energy from the mean flow to the eddy field—a definition sometimes used by numerical modelers. At times, western boundary currents

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C. Chavanne, P. Flament, D. Luther, and K-W. Gurgel

1. Introduction The purpose of this paper is to investigate the effects of mesoscale currents on internal tide propagation. This is motivated by observations of semidiurnal currents in the Kauai Channel ( Chavanne et al. 2010 , hereafter Part I ) during the Hawaii Ocean Mixing Experiment (HOME; Rudnick et al. 2003 ; Pinkel and Rudnick 2006 ). Part I compares the observed coherent (i.e., phase locked with astronomical forcing) semidiurnal currents with numerical predictions of the tides in

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Peter Jan van Leeuwen and Will P. M. de Ruijter

1. Introduction In the World Ocean several places exist where large-scale ocean currents retroflect (i.e., make an anticyclonic turn of more than 90°) after separation. Examples are the Agulhas Current, the North Brazil Current, the Brazil Current, and the East Australian Current. A common observed feature of all these systems is that they are unsteady and shed rings. In a series of papers (e.g., Nof and Pichevin 1996 , hereafter NP ) state that under a rather restricting set of conditions

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