Oceanography The Official Magazine of
The Oceanography Society
Volume 21 Issue 02

View Issue TOC
Volume 21, No. 2
Pages 72 - 76

OpenAccess

HANDS-ON OCEANOGRAPHY • A Laboratory Demonstration of Coriolis Effects on Wind-Driven Ocean Currents

David Beesley | University of Massachusetts, Dartmouth, MA, USA
Jason Olejarz | University of Massachusetts, Dartmouth, MA, USA
Amit Tandon | Physics Department, University of Massachusetts, Dartmouth, MA, USA
John Marshall | Program in Atmospheres, Oceans, and Climate, Department of Earth, Atmospheric, and Planetary Sciences, MIT, and MIT Climate Modeling Initiative, Cambridge, MA, USA

Jump to
Citation Copyright & Usage
First Paragraph

Purpose of Activity

Here we study the mechanism by which the wind drives ocean circulation. We induce cyclonic and anticyclonic circulation by blowing air over the surface of a rotating tank of water using fans co-rotating with the turntable, as sketched in Figure 1. The Ekman layers and patterns of upwelling and downwelling can be visualized by using dye crystals and paper dots.

The flow within the surface Ekman layer associated with the action of the wind is convergent in anticyclonic flow and divergent in cyclonic flow if the apparatus is rotating cyclonically (Ω > 0, corresponding to the northern hemisphere), as sketched in Figure 2. The convergent flow drives downward vertical motion (called Ekman pumping, Figure 2a); the divergent flow drives upward vertical motion from beneath (called Ekman suction, Figure 2b).

The experiment demonstrates how divergence in Ekman transport leads to vertical motion. Students visualize how continuity of the flow leads to upwelling in a cyclone and downwelling in an anticyclone, which then helps make connections with gyre-scale ocean circulation. Students learn how to visualize circulation at the surface and at depth using paper dots and dye tracers.

Citation

Beesley, D., J. Olejarz, A. Tandon, and J. Marshall. 2008. Hands-on oceanography: A laboratory demonstration of coriolis effects on wind-driven ocean currents. Oceanography 21(2):72–76, https://doi.org/10.5670/oceanog.2008.60.

Copyright & Usage

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.