EOS, Transactions, AGU, 2000 Ocean Science
Meeting, Vol. 80, No. 49, December 07, 1999, page OS1
Different sediment transport and particle motion during glacial-to-interglacial
cycles of the ocean paleocirculation
Earth System Science Center, Pennsylvania State University,
University Park, PA 16802-2711
The Last Glacial Maximum
(LGM) and subsequent meltwater events give examples of vigorous changes of the
deep-sea ocean circulation that have been reasonably well modeled using stand-alone
ocean models. However, there are still questions whether these simulations can
be verified by comparison to geological record, or by some other means to increase
their credibility. The major unknown is whether millennial-scale changes of
the circulation can be clearly seen in ocean sediment, and whether the water
mass motion can be effectively traced in large-scale ocean models. We present
trajectories and sedimentation patterns obtained using simulations of the LGM
and meltwater ocean currents in MOM-2 ocean model. Additional passive tracers
and lagrangian trajectories help to identify water paths, whereas comparison
of modeled and observed sedimentation patterns reveal the model performance
in tracing the circulation changes. Different mixing schemes are used to address
model sensitivity to changes of convection regime - key process in the glacial
to interglacial variability of the deep-sea currents. We show that it is possible
to compare simulated and observed inorganic sedimentation patterns, at least
in the regions of sediment drifts. Different sea-surface sources of eolian sediment
were used to address the problem of usability of the eolian sediment as an additional
tracer. It is shown that the signature of the deep-ocean currents is recognizable
in the net inorganic sediment accumulation patterns and is not completely overwhelmed
by the sea-surface signal.
Left part; click
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Middle part; click on the
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Left part; click on the poster
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