1. The Cromwell Current and its effects on the Galapagos Islands
Jennifer Walker
Physical Oceanography
Fall 2014

2. What is the Cromwell Current?
Discovered in 1951
Last major ocean current to be found
Cromwell led expedition following year

4. General Characteristics
Geostrophic equilibrium
Symmetrical about equator
200 m thick
300 km wide
Velocities up to 1.5 m/s
Core coincides with thermocline
Temp of 13 degrees C

5. Variations in the current
Seasonal fluctuations of wind affect transport
Velocity and transport decrease to east
Core depth varies from 50 m in E to 200 m in W
Galapagos is eastern terminus

6. The Cromwell Current and the Galapagos Islands
Galapagos: 13 islands, 1000 km W of Ecuador
Weakens velocities
Undercurrent splits
Upwelling

7. The Current and Galapagos Biology
Upwelling
High oxygen
High nutrients
Increased primary production
Effect of El Nino

8. References
Knauss, J.A., 1997, Introduction to Physical Oceanography, Waveland Press, Inc., Illinois, pp. Knauss, J.A., 1961, The Cromwell Current, Scientific American, Inc., Liu, Y., L. Xie, J.M. Morrison, D. Kamykowski, and W.V. Sweet, 2014, Ocean circulation and water mass characteristics around the Galapagos Archipelago simulated by a multiscale nested ocean circulation model, International Journal of Oceanography, 2014, Pak, H. and J.R. Zaneveld, 1973, The Cromwell Current on the east side of the Galapagos Islands, Journal of Geophysical Research, 78, Philander, S.G., 1973, Equatorial Undercurrent: Measurements and theories, Reviews of Geophysics and Space Physics, 11, Stewart, R., 2002, Introduction to Physical Oceanography, Chapter 14.