Steve Hovan, Department of Geoscience, presented his research at the 2010 Ocean Sciences Meeting in Portland, Oregon. Dr. Hovan and his colleagues at the University of California–Santa Cruz have been investigating the paleoclimate and paleoceanographic conditions of our planet through the use of deep sea sediments.
“Pliocene records of ITCZ, wind field strength, and thermocline temperatures in the Eastern Equatorial Pacific”
S.A. Hovan, A. Ravelo, H.L. Ford
The eastern equatorial Pacific region is particularly important to our understanding of paleoceanographic/paleoclimatic changes because of the role it plays in global heat transport and oceanic primary productivity. Strong connections exist between atmospheric (trade wind intensity, intertropical convergence zone location) and oceanic (surface currents, thermocline depth, productivity) systems, making it an ideal place to examine how these components change during important climatic transitions.
During the Pliocene for example, when global climates cooled from relatively warm unipolar conditions to a state dominated by glacial-interglacial cycles, records of eolian sediments suggest the Pliocene ITCZ was located farther north than its modern latitudinal average. At the same time, oceanic records suggest a permanent El Niño-like state with sea surface temperature reconstructions showing the eastern tropical Pacific 2-3 deg C warmer than today. We compare new high-resolution (temporal) multiproxy data generated from a latitudinal transect of cores from ODP Legs 138 and 199 to gain a clearer understanding about the timing and relationship of changes of several key components of the climate system: a) the location of the ITCZ, b) wind field strength, c) thermocline temperatures, and d) paleoproductivity as conditions in the tropical Pacific transitioned from the warmer Pliocene conditions into the cooler glacial cycles of the Pleistocene.