Clim. Past Discuss., 9, 6375-6395, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper is under review for the journal Climate of the Past (CP).
The impacts of Meltwater Pulse-1A in the South Atlantic Ocean deep circulation since the Last Glacial Maximum
J. M. Marson1, I. Wainer1, Z. Liu2, and M. M. Mata3
1Oceanographic Institute, University of São Paulo, São Paulo, SP, Brazil
3Institute of Oceanography, Federal University of Rio Grande-FURG, Rio Grande, RS, Brazil
2Center for Climatic Research and Department of Atmospheric and Oceanic Sciences, University of Wisconsin, Madison, USA

Abstract. Since 21 000 yr ago, the oceans have received large amounts of freshwater in pulses coming from the melting ice sheets. A specific event, known as meltwater pulse 1A (MWP-1A), has been identified in sea-level and temperature proxy records as responsible for the increase of ~20 m in sea level in less than 500 yr. Although its origin and timing are still under discussion, MWP-1A seems to have had a significant impact on several components of the climatic system. The present work aims to elucidate these impacts on the water mass distribution of the South Atlantic Ocean through the analysis of a transient simulation of the climate evolution from the Last Glacial Maximum to Present Day using a state-of-art CGCM, the National Center for Atmospheric Research Community Climate System Model version 3 (NCAR CCSM3). Results show that the freshwater discharge associated with the timing of MWP-1A was crucial to establish the present thermohaline structure associated with the North Atlantic Deep Water, marking the transition between a shallower and a deeper Atlantic Meridional Overturning Circulation.

Citation: Marson, J. M., Wainer, I., Liu, Z., and Mata, M. M.: The impacts of Meltwater Pulse-1A in the South Atlantic Ocean deep circulation since the Last Glacial Maximum, Clim. Past Discuss., 9, 6375-6395, doi:10.5194/cpd-9-6375-2013, 2013.
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