Project Title: Integrated Multi-Proxy Analyses of Mid-Pliocene Ocean Temperatures for an Improved Paleoclimate Reconstruction
Mendenhall Fellow: Marci Robinson, (703) 648-5291, firstname.lastname@example.org
Duty Station: Reston, VA
Start Date: October 1, 2007
Education: Ph.D. (Environmental Science), George Mason University, 2007
Research Advisors:Harry Dowsett, (703) 648-5282, email@example.com; Alan Haywood, firstname.lastname@example.org
Project Description: The mid-Pliocene is the most recent period of global warmth analogous to the future warming predicted by climate models (IPCC, 2001). The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project is dedicated to reconstructing global synoptic mid-Pliocene conditions (Dowsett and others, 1999). PRISM sea-surface temperature (SST) reconstructions are the most comprehensive pre-Pleistocene data sets available for analysis of warmer-than-present climates and for future climate modeling experiments, but they are deficient in that high latitude regions are underrepresented due to limits of the paleotemperature proxy utilized. Traditionally, PRISM SST estimates have been based on assemblage data of fossil foraminifera, diatoms, ostracodes and pollen. Though quantitative analytical procedures utilizing planktic foraminiferal assemblages remain the mainstay for SST reconstructions, additional paleothermometry techniques offer alternate pathways to high latitude SST estimation and temperature estimation at depth.
The goal of this research is threefold:
- to expand PRISM SST coverage in the high latitudes by providing SST estimates at new high latitude sites using independent proxies of paleotemperature (i.e., Mg/Ca ratios and alkenone unsaturation indices),
- to re-examine existing PRISM locations to estimate SSTs using these paleothermometry techniques in order to understand the seasonal, depth and temperature relationships among multi-proxy estimates and to reconcile disagreement among proxies when necessary, and
- to provide vertical temperature gradient estimates at new and existing PRISM sites for a better understanding of thermocline behavior during the mid-Pliocene and integration into a three-dimensional ocean temperature data set.
The improved PRISM reconstruction will reflect not only a greater representation of data points in the high latitudes, but also an improved understanding of the seasonality and depth stratification of the mid-Pliocene surface layer, adding a depth component to the surface temperature reconstruction. Integration of this improved SST reconstruction with available bottom water temperature estimates and vegetation and ice models will provide a three-dimensional mid-Pliocene ocean temperature reconstruction appropriate for use by fully coupled ocean-atmosphere general circulation climate models.
Dowsett, H.J., Barron, J.A., Poore, R.Z., Thompson, R.S., Cronin, T.M., Ishman, S.E. and Willard, D.A., 1999, Middle Pliocene paleoenvironmental reconstruction: PRISM2: U.S. Geological Survey Open-File Report 99-535 (http://pubs.usgs.gov/openfile/of99-535/).
Intergovernmental Panel on Climate Change, 2001, Climate change 2001 in Houghton, J.T., ed., The science of climate change: Cambridge University Press.
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