Drift current circulation patterns, II
West-directed flow in north & south equatorial currents driven by trade winds
Equatorial countercurrent, a narrow region of east-directed flow, separates N & S equatorial currents
Western boundary currents are distinct, narrow (<100 km wide), swift (water velocities are >100 km/day), & deep (affect water to depth of 2 km)
Eastern boundary currents are broad (~1000 km wide), weak (water velocities are ~ 10’s km/day), & shallow (affect water to depth = ~ 500 m)
Smaller, less well developed current gyres occur in sub-polar & polar regions