HR: 13:40h
AN: PP33C-01 INVITED    [Abstracts]
TI: Orbital influences on paleosalinity indicators
AU: * LeGrande, A N
EM: legrande@giss.nasa.gov
AF: NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University, 2880 Broadway, New York, NY 10025, United States
AU: Schmidt, G A
EM: gschmidt@giss.nasa.gov
AF: NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University, 2880 Broadway, New York, NY 10025, United States
AB: Water isotopes records collectively provide a set of the most extensive proxy evidence for past climate. Implied in the interpretation of these records is a set relationship between water isotopes and climate. In particular,the modern regional relationships between salinity and seawater δ¹⁸O are used to reconstruct paleosalinity. However, on orbital timescales and during abrupt climate change events, the climate goes under significant reorganization. These climate changes impact the hydrologic cycle, including water isotopes. As such, the relationship between water isotopes and climate is unlikely to remain constant through time. We assess the relationship between water isotopes and climate using different simulations of Holocene climate using GISS ModelE-R, a fully coupled atmosphere-ocean General Circulation Model equipped with water isotopes, as well as other tracers, making it ideal for performing exact comparisons with the proxy record of past climate change. We find that the relationships between water isotopes and salinity as well as surface air temperature and precipitation are different at decadal timescales than at orbital (millennial) timescales and that this relationship also changes during abrupt climate change events. In particular, the altering of the amount of water exported from the tropics, as well as exchanged between ocean basins, has profound impacts on the relationship between water isotopes and climate. Thus the relationship between water isotopes and climate is not constant through time.
DE: 1030 Geochemical cycles (0330)
DE: 1622 Earth system modeling (1225)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4928 Global climate models (1626, 3337)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting