| Title | A modeling sensitivity study of the influence of the Atlantic meridional overturning circulation on neodymium isotopic composition at the last glacial maximum |
| Author | Arsouze, T.; Dutay, J.; Kageyama, M.; Lacan, F.; Alkama, R.; Marti, O.; Jeandel, C. |
| Author Affil | Arsouze, T., Laboratoire des Sciences du Climat et de l'Environnement, Gif- Sur-Yvette, France. Other: Laboratoire d'Etudes en Géophysique et Océanographie Spatiale, France |
| Source | Climate of the Past, 4(3), p.191-203, . Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814- 9324 |
| Publication Date | 2008 |
| Notes | In English. Published in Climate of the Past Discussion: 18 March 2008, http://www.clim-past- discuss.net/4/309/2008/cpd-4-309-2008.html; accessed in October, 2009. 64 refs. Ant. Acc. No: 87328. GeoRef Acc. No: 296658 |
| Index Terms | atmospheric circulation; climatic change; glacial geology; ice sheets; metals; models; paleoclimatology; simulation; topography; Atlantic Ocean--North Atlantic; Southern Ocean; Atlantic Ocean; bathymetry; Cenozoic; climate change; climate effects; climate forcing; climatic controls; deep- water environment; Holocene; last glacial maximum; neodymium; North Atlantic; numerical models; ocean circulation; paleo- oceanography; paleocurrents; paleosalinity; Quaternary; rare earths; thermohaline circulation |
| Abstract | Using a simple parameterization that resolves the first order global Nd isotopic composition (hereafter expressed as #2ENd in an Ocean Global Circulation Model, we have tested the impact of different circulation scenarios on the #2ENd in the Atlantic for the Last Glacial Maximum (LGM), relative to a modern control run. Three different LGM freshwater forcing experiments are performed to test for variability in the #2ENd oceanic distribution as a function of ocean circulation. Highly distinct representations of the ocean circulation are generated in the three simulations, which drive significant differences in #2ENd, particularly in deep waters of the western part of the basin. However, at the LGM, the Atlantic is more radiogenic than in the modern control run, particularly in the Labrador basin and in the Southern Ocean. A fourth experiment shows that changes in Nd sources and bathymetry drive a shift in the #2ENd signature of the basin that is sufficient to explain the changes in the #2ENd signature of the northern end-member (NADW or GNAIW glacial equivalent) in our LGM simulations. All three of our LGM circulation scenarios show good agreement with the existing intermediate depth #2ENd paleo-data. This study cannot indicate the likelihood of a given LGM oceanic circulation scenario, even if simulations with a prominent water mass of southern origin provide the most conclusive results. Instead, our modeling results highlight the need for more data from deep and bottom waters from western Atlantic, where the #2ENd change in the three LGM scenarios is the most important (up to 3 #2ENd. This would also aid more precise conclusions concerning the evolution of the northern end-member #2ENd signature, and thus the potential use of #2ENd as a tracer of past oceanic circulation. |
| URL | http://www.clim-past.net/4/191/2008/cp-4-191-2008.pdf |
| Publication Type | journal article |
| Record ID | 64001769 |