Sensitivity of the ocean-atmosphere carbon cycle to ice-covered and ice-free conditions in the Nordic Seas during the Last Glacial Maximum [An article ... Palaeoclimatology, Palaeoecology]

This digital document is a journal article from Palaeogeography, Palaeoclimatology, Palaeoecology, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
A global carbon-cycle box model forced by an ocean-general circulation model (OGCM) is used to investigate how different sea-surface reconstructions for the northern North Atlantic Ocean (Nordic Seas) for the Last Glacial Maximum (LGM) affect the ocean-atmosphere carbon cycle via changes in the large-scale thermohaline circulation. For perennial sea-ice cover in the Nordic Seas [CLIMAP, Chart Ser. (Geol. Soc. Am.) MC-36 (1981)], the model-predicted deep-water formation areas, @d^1^3C distribution and ^1^4C ventilation ages are partly inconsistent with palaeoceanographic data for the glacial Atlantic Ocean. Considering ice-free conditions during LGM summer in the Nordic Seas [Weinelt et al., Palaeoclimatology 1 (1996) 283] brings the model results in better agreement with palaeoceanographic findings, thus supporting this particular sea-surface reconstruction. For both LGM scenarios, the ocean circulation model simulates a reduction in the export of North Atlantic Deep Water (NADW) to the Southern Ocean by 50% compared to today. The effect of changes in the intensity of the thermohaline circulation on atmospheric CO"2 content alone is rather small, accounting for approximately 20% of the net CO"2 lowering during the LGM.