Sinking particle fluxes from the euphotic zone over the continental slope of an eastern boundary current region

Abstract A linear stability analysis of a meridional boundary current on the beta plane is presented. The boundary current is idealized as a constant-speed meridional jet adjacent to a semi-infinite motionless far field. The far-field region can be situated either on the eastern or the western side of the jet, representing a western or an eastern boundary current, respectively. It is found that when unstable, the meridional boundary current generates temporally growing propagating waves that transport energy away from the locally unstable region toward the neutral far field. This is the so-called radiating instability and is found in both barotropic and two-layer baroclinic configurations. A second but important conclusion concerns the differences in the stability properties of eastern and western boundary currents. An eastern boundary current supports a greater number of radiating modes over a wider range of meridional wavenumbers. It generates waves with amplitude envelopes that decay slowly with distance from the current. The radiating waves tend to have an asymmetrical horizontal structure—they are much longer in the zonal direction than in the meridional, a consequence of which is that unstable eastern boundary currents, unlike western boundary currents, have the potential to act as a source of zonal jets for the interior of the ocean.

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Climate change and wind intensification in coastal upwelling ecosystems

Science ◽

10.1126/science.1251635 ◽

2014 ◽

Vol 345 (6192) ◽

pp. 77-80 ◽

Cited By ~ 245

Author(s):

W. J. Sydeman ◽

M. García-Reyes ◽

D. S. Schoeman ◽

R. R. Rykaczewski ◽

S. A. Thompson ◽

...

Keyword(s):

Climate Change ◽

Coastal Upwelling ◽

Meta Analysis ◽

Boundary Current ◽

Eastern Boundary ◽

Warming Pattern ◽

Eastern Boundary Current ◽

Coastal Winds ◽

Variable Support ◽

Current Systems

In 1990, Andrew Bakun proposed that increasing greenhouse gas concentrations would force intensification of upwelling-favorable winds in eastern boundary current systems that contribute substantial services to society. Because there is considerable disagreement about whether contemporary wind trends support Bakun’s hypothesis, we performed a meta-analysis of the literature on upwelling-favorable wind intensification. The preponderance of published analyses suggests that winds have intensified in the California, Benguela, and Humboldt upwelling systems and weakened in the Iberian system over time scales ranging up to 60 years; wind change is equivocal in the Canary system. Stronger intensification signals are observed at higher latitudes, consistent with the warming pattern associated with climate change. Overall, reported changes in coastal winds, although subtle and spatially variable, support Bakun’s hypothesis of upwelling intensification in eastern boundary current systems.

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Production regimes in four Eastern Boundary Current systems

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/j.dsr2.2003.07.015 ◽

2003 ◽

Vol 50 (22-26) ◽

pp. 3199-3221 ◽

Cited By ~ 175

Author(s):

Mary-Elena Carr ◽

Edward J. Kearns

Keyword(s):

Boundary Current ◽

Eastern Boundary ◽

Eastern Boundary Current ◽

Current Systems

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Detiding Shipboard ADCP Data in Eastern Boundary Current

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2010jtecho697.1 ◽

2011 ◽

Vol 28 (1) ◽

pp. 94-103 ◽

Cited By ~ 4

Author(s):

Heriberto Jesus Vazquez ◽

Jose Gomez-Valdes ◽

Modesto Ortiz ◽

Juan Adolfo Dworak

Keyword(s):

Least Squares ◽

Baja California ◽

Gaussian Function ◽

Kelvin Wave ◽

Boundary Current ◽

Mean Flow ◽

Wave Dynamics ◽

Eastern Boundary ◽

Eastern Boundary Current ◽

Adcp Data

Abstract Spatiotemporal fitting by the least squares method is commonly applied to distinguish the mean flow from the tidal current from shipboard ADCP data in coastal ocean. To analyze this technique in a pelagic region of an eastern boundary current system, a 6-yr period of shipboard ADCP data off Baja California is examined. A diverse set of basis functions is studied and a global tidal model is used for comparison purposes. The Gaussian function together with a nodal configuration of one node in the middle and close to the coast of the region is the best option. However, to obtain the optimal solution, the geostrophic flow, which is stronger than the tidal flow and highly variable off Baja California, might be removed prior to fitting the data. In general, the semimajor axis of the tidal ellipse (M2) is parallel to the coast and the phase speed is poleward and parallel to the coast, in agreement with Kelvin wave dynamics. Because the tides in eastern boundary currents are explained by Kelvin wave dynamics, the use of both the velocity field without geostrophic variability and the Gaussian function in the spatiotemporal fitting by least squares technique is a promising tool for detiding shipboard ADCP data from these systems.

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