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

. Because of the presence of continents, boundary currents that are meridional or close to meridional are present on both sides of most ocean basins. Unstable boundary currents can be an important source of eddy kinetic energy. If the instabilities are radiating, then the energy of the disturbances will be transported long distances and will be able to potentially affect the mean circulation and its variability in the interior of the basin. Radiating instabilities propagate energy away from the locally

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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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Astrid Pacini, Robert S. Pickart, Isabela A. Le Bras, Fiammetta Straneo, N. Penny Holliday, and Michael A. Spall

1. Introduction The boundary current system encircling the Labrador Sea plays a pivotal role in the warm-to-cold water mass transformation that occurs in the sea, which contributes to the Atlantic meridional overturning circulation (AMOC). In the interior of the basin, newly ventilated Labrador Sea Water is formed through deep convection (e.g., Clarke and Gascard 1983 ; The Lab Sea Group 1998 ; Pickart et al. 2002 ). This weakly stratified water mass helps to maintain the hydrographic

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Charles W. McMahon, Joseph J. Kuehl, and Vitalii A. Sheremet

1. Introduction a. Motivation Currents forming along the boundaries of the oceans are strong and ubiquitous. In select locations, such boundary currents encounter a gap in their supporting boundary, resulting in a scenario where the current must traverse the gap, either by leaping across it or by penetrating into it. The nature and variability of these configurations have important influences on the basin that is connected to the larger ocean through the gap. Examples of such situations are the

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Michael A. Spall

baroclinic instability (e.g., Gawarkiewicz and Chapman 1995 ; Jiang and Garwood 1996 ), which includes a downwelling component. While there are some regions and times for which this localized, isolated forcing is applicable, over most of the high latitude and marginal seas there exist strong cyclonic boundary currents that have not been considered in these problems ( Cuny et al. 2002 ; Mauritzen 1996a , b ). These boundary currents transport large amounts of heat and freshwater into/out of the basins

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Stefano Pierini, Pierpaolo Falco, Giovanni Zambardino, Thomas A. McClimans, and Ingrid Ellingsen

1. Introduction Western boundary currents (WBCs) are very intense currents that flow along the western boundaries of the oceans and owe their peculiar structure to the sphericity of the earth, which generates the so-called planetary beta effect ( Stommel 1948 ; Munk 1950 ). The Gulf Stream (GS) and Kuroshio are notable examples of WBCs belonging to the subtropical gyres of the North Atlantic and Pacific Oceans, respectively. The effect of WBCs and of their respective extensions on climate is

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Vitalii A. Sheremet and Joseph Kuehl

1. Introduction The interaction of a boundary current with bathymetric features such as a gap in the ridge or a strait between two islands is an important and interesting oceanographic problem. Examples include western boundary currents such as the Gulf Stream leaping from the Yucatan to Florida or the Kuroshio leaping from Luzon to Taiwan and shelfbreak currents such as the one leaping from the Scotian shelf to Georges Bank ( Cho et al. 2002 ; the so-called Scotian Shelf Water crossover event

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Thierry Pichevin, Steven Herbette, and France Floc’h

1. Introduction a. The problem Though the separation of western boundary currents in the ocean is a well-known feature, it is not yet totally understood. In the cases of the North Brazil ( Fig. 1 ) and Agulhas Currents ( Fig. 2 ), the separation takes place abruptly and leads to a curve of the coastal current of more than 90° over a few hundred kilometers. This extreme change in the direction of the flow is accompanied by the shedding of eddies, which can travel thousands of kilometers and thus

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Xiaoting Yang, Eli Tziperman, and Kevin Speer

1. Introduction Intense currents along the western boundaries, for example, the Gulf Stream and underlying deep western boundary current in the North Atlantic Ocean, and similar western boundary currents in other basins, are striking features of the global ocean circulation. The ocean interior flow is, in contrast, typically dominated by an energetic eddy field, from which the large-scale gyres emerge in a time average. The basic dynamics of the western boundary currents have been explained by

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N. V. Zilberman, D. H. Roemmich, S. T. Gille, and J. Gilson

1. Introduction Western boundary currents (WBCs) represent the primary route for the export of tropical water masses from low to midlatitudes, including elements of the shallow meridional overturning circulations ( Talley 2008 ; Huang 2010 ). The strength and variability of WBCs affect air–sea fluxes of heat and moisture and influence storm-track evolution and extreme weather event frequency in WBC regions ( Cai et al. 2012 ). WBCs and recirculation are not well represented in coupled climate

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