Response of the Atlantic Ocean circulation to Greenland Ice Sheet melting in a strongly-eddying ocean model

Abstract

The sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to high-latitude freshwater input is one of the key uncertainties in the climate system. Considering the importance of the AMOC for global heat transports, and the vulnerability of the Greenland Ice Sheet (GrIS) to global warming, assessing this sensitivity is critical for climate change projections. Here we present a unique set of computational experiments to investigate the adjustment of the AMOC to enhanced melt water from the GrIS under present-day conditions. For the first time, the response in a global, strongly-eddying ocean model is systematically compared to that of an ocean model typical of IPCC-class climate models. We find that the overall decline of the AMOC on decadal time scales is quantitatively similar (<10%) in the two configurations. Nonetheless, the transient response is significantly different, as the AMOC decline and reduction in wintertime convection is markedly more gradual and persistent in the strongly-eddying configuration. © 2012 by the American Geophysical Union.