New twist on an old ocean circulation theory

A rainbow glows over the Bay of Bengal. Credit: NOAA

One of the foundational principles of modern oceanography is that ocean surface currents on our rotating planet will be deflected to the right of the winds in the Northern Hemisphere and to the left of the winds in the Southern Hemisphere.

While this principle, first explained by the Swedish oceanographer Vagn Walfrid Ekman in 1905, applies everywhere on Earth, there’s more to the story, including a twist described in new research by an international team led by a scientist with NOAA’s Pacific Marine Environmental Laboratory (PMEL). In the Bay of Bengal, analysis of data collected by a long-term deepwater surface moored buoy showed currents directed to the left of the surface winds.