2. Analysis of Ocean Circulation and Ocean-Atmosphere Modeling of Future Climate Scenarios

The importance of paleoclimate reconstruction is recognized in the U.S. Climate Change Science Program (CCSP), in assessment reports of the Intergovernmental Panel on Climate Change (IPCC, 2007), the National Academy Report on Abrupt Climate Change (NRC, 2002), and U.S. Geological Survey (USGS) strategic planning documents. While much can be gained by careful analysis of single time series from strategic locations, only spatial or geographic reconstructions can provide synoptic information that may be analogous to future climate conditions. Much paleoclimate work is focused on the Holocene, yet even the most conservative coupled ocean-atmosphere general circulation climate models (COAGCMs) indicate that conditions likely to occur during the next century were last encountered during the mid-Pliocene (~3Ma). The USGS has invested many resources in developing a mid-Pliocene paleoenvironmental reconstruction (PRISM) that has been successfully used with COAGCMs and now seeks to enhance the existing deep ocean reconstruction with new paleo-circulation data. Surface and deep ocean temperature reconstructions based upon PRISM data suggest an enhanced Atlantic meridional overturning circulation (AMOC) during the mid-Pliocene in contrast to conventional understanding of the effects of surface warming which would suggest a slowing of the AMOC (Dowsett, 2007; Dowsett and others, 2009). The role of the AMOC is central to the understanding of Pliocene warming and has direct consequences for modeling future climate conditions.

We seek a postdoctoral candidate to quantitatively evaluate mid-Pliocene deep ocean circulation using carbon isotopes and/or paleo-salinity proxies and to integrate these data with existing USGS (PRISM) deep-ocean and sea-surface temperature data sets (http://geology.er.usgs.gov/eespteam/prism/index.html). The successful candidate will generate and analyze carbon isotope and possibly other data from existing cores in the Atlantic, Arctic, Southern Ocean, and Pacific regions. He/she will investigate theories and observations regarding the effects of sea-surface temperature warming on AMOC, utilizing climate-modeling ties with the NASA Goddard Institute of Space Sciences (GISS), the Hadley Center, and the National Center for Atmospheric Research (NCAR) through a formal relationship between the USGS and these modeling groups (Pliocene Model Intercomparison Project, PlioMIP, a subproject of PMIP3) (Otto-Bliesner and others, 2009)

The successful Fellow will be expected to integrate these new results with ongoing USGS collaborative projects using coupled ocean-atmosphere COAGCM’s. While the general topic of deep ocean circulation must be addressed, we welcome innovative proposals that also address any specific area within the collaborative study of this last period of significant global warming.

References

Dowsett, H.J., 2007, The PRISM paleoclimate reconstruction and Pliocene sea-surface temperature, in Williams, M., Haywood, A.M., Gergory, F.J. and Schmidt, D.N., eds., Deep-time perspectives on climate change: Marrying the signal from computer models and biological proxies: The Micropaleontological Society Special Publications: London, The Geological Society, p. 459–480.

Dowsett, H.J., Chandler, M.A. and Robinson, M.M., 2009, Surface temperatures of the mid-Pliocene North Atlantic Ocean: Implications for future climate: Philosophical Transactions of the Royal Society A, The Pliocene: A vision of Earth in the late twenty-first century?: v. 367, p. 69–84, doi:10.1098/rsta.2008.0213.

IPCC, 2007, Climate change 2007: The physical science basis: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, in Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M. and Miller, H.L., eds.: Cambridge, U.K., and New York, N.Y., U.S.A., Cambridge University Press. (http://www.ipcc.ch/)

National Research Council Committee on Abrupt Climate Change, 2002, Abrupt climate change: Inevitable surprises: Washington, D.C., National Academies Press, 244 p.

Otto-Bliesner, B.L., Joussaume, S., Harrison, S.P., Abe-Ouchi, A. and Braconnot, P., 2009, PMIP2 workshop: PAGES News, v. 17, no. 1, p. 42–43.

Proposed Duty Station: Reston, VA

Areas of Ph.D.: Geology, paleoceanography, paleoclimatology, geochemistry, organic geochemistry, paleontology (candidates holding a Ph.D. in other disciplines but with knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications: Applicants must meet one of the following qualifications: Research Geologist, Research Chemist

(This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Research Advisor(s): Harry Dowsett, (703) 648-5282, hdowsett@usgs.gov; Alan Haywood (University of Leeds), (0044) (0) 1223-221420, earamh@leeds.ac.uk

Human Resources Office contact: Brian Arnold-Renicker, (703) 648-7468, brenicke@usgs.gov

Summary of Opportunities