Holocene evolution of the North Atlantic subsurface transport
Janne Repschläger1,a, Dieter Garbe-Schönberg1, Mara Weinelt2, and Ralph Schneider11Institute of Geosciences, Kiel University, 24118 Kiel, Germany 2Institute of Prehistoric and Protohistoric Archaeology, Kiel University, 24118 Kiel, Germany anow at: Climate Geochemistry Department, Max-Planck-Institute for Chemistry, 55128 Mainz, Germany
Received: 09 Nov 2016 – Accepted for review: 20 Nov 2016 – Discussion started: 21 Nov 2016
Abstract. Previous studies suggested that short term freshening events in the subpolar gyre can be counterbalanced by interactions with the subtropical gyre and thus stabilize the Atlantic Meridional Overturning Circulation (AMOC). However, little is known about the intergyre transport pathways. Here, we reconstruct surface and subsurface transport between the subtropical and polar North Atlantic during the last 10000 years, by combining new temperature and salinity reconstructions obtained from surface and subsurface dwelling foraminifera with published data from the tropical and subpolar North Atlantic and published foraminiferal abundance data from the subtropical North Atlantic. These observations imply an overall stable warm surface water transport. Subsurface warm water transport started at about 8 ka with subtropical heat storage, and reached its full strength at about 7 ka, probably associated with the onset of the modern AMOC mode. Comparison of different potential forcing mechanisms suggests a freshwater control on these ocean transport changes.
Repschläger, J., Garbe-Schönberg, D., Weinelt, M., and Schneider, R.: Holocene evolution of the North Atlantic subsurface transport, Clim. Past Discuss., doi:10.5194/cp-2016-115, in review, 2016.