Simulation of the Oxygen Isotope Ratio in Foraminiferal Carbonate During Heinrich Event 1: The Significance of Subsurface Warming
Abstract
We use a climate model of intermediate complexity to simulate the effect of deglacial meltwater discharge on the hydrogaphy of the Atlantic Ocean. Our climate model contains active hydrologic and isotopic cycles. This allows us to compare the model results to measurements of the oxygen-18/oxygen-16 ratio from fossil carbonate shells of planktic and benthic foraminifera (δ 18Oc) that pertain to Heinrich event 1. Both model and data show a large anomaly with respect to the last glacial maximum in the subsurface waters of the southern hemisphere. We argue that this anomaly represents a warming that is signifiant of any slow-down of the meridional overturning circulation, which in this case is in response to the meltwater input to high northern latitudes. To this end we use the model output to disentangle the competing effects of changes in temperature and the oxygen-18/oxygen-16 ratio of sea water (δ 18Ow) on the oxygen-18/oxygen-16 ratio as preserved in foraminiferal carbonate. It turns out that the temperature change by far outweighs the change in δ 18Ow.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004AGUSM.A52B..06P
- Keywords:
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- 1620 Climate dynamics (3309);
- 4255 Numerical modeling;
- 4267 Paleoceanography;
- 4536 Hydrography;
- 4870 Stable isotopes