WESTERN AND EASTERN BOUNDARY CURRENTS

Schematic Model of Boundary Currents

Explanation of Western Intensification

Western Intensification from Beta effect

Coriolis constant

Coriolis changing with latitude

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Ocean Color

Low Productivity in Western Boundary Currents

- major pathway for heat, salt and nutrients transport to high latitudes- frontal processes of important ecological implications

General Origin and Path of Gulf Stream

Sea Surface Temperature image of the Gulf Stream, in yellow and orange. Data from the MODIS instrument on the Aqua satellite. Image provided by Norman Kuring, NASA/GSFC. (oceanmotion.org)

Complete View of the Gulf Stream

Poleward transport of heat

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Along-stream Momentum Balance

Inertia, Coriolis, Pressure Gradient

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Across-stream Momentum Balance

Coriolis and Pressure Gradient = Geostrophy

Gulf Stream Eddies

May 1997

Temperature cross-section of a cold-core ring in the Gulf Stream

Link to Gulf Stream Tutorial

KUROSHIO CURRENT

(Black Water)

Long-term mean geopotential anomaly (converted to meters) relative to 1000 db (Hasunuma and Yoshida, 1978)

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Surface mean currents in the East China Sea derived from geopotential anomaly data from 1953-1984 (Qiu and Imasato, 1990).

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with respect to 700 db.

(Guo et al., 2003)

Velocity profile along the ASUKA line: Geostrophic calculation with a reference level at 2000 m in the deep area and at the bottom in the shallow area (S. Imawaki 1995) Contour interval is 0.1 m/s; shaded areas denote negative values.

Kuroshio path in 2000 (from the Bulletin of Oceanic Conditions, published by the Japanese Coast Guard)

EASTERN BOUNDARY CURRENTS

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WeakWinds

StrongWinds

PF = Polar Flow

CJ = Coastal Jet

GF = Geostrophic Flow

(From Tomczak)