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

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

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

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

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

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

References Knauss, J.A., 1997, Introduction to Physical Oceanography, Waveland Press, Inc., Illinois, 146-151pp. Knauss, J.A., 1961, The Cromwell Current, Scientific American, Inc., 105-119. 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, 1-16. Pak, H. and J.R. Zaneveld, 1973, The Cromwell Current on the east side of the Galapagos Islands, Journal of Geophysical Research, 78, 7845-7859. Philander, S.G., 1973, Equatorial Undercurrent: Measurements and theories, Reviews of Geophysics and Space Physics, 11, 513-570. Stewart, R., 2002, Introduction to Physical Oceanography, Chapter 14.