Oceanic response to topography and orbital forcing during the MIS31: The reversal effect of both forcing

Abstract:

Earth climate has been punctuated by cold (glacial) and warm (interglacial) intervals associated with modification of the planetary orbit and subsequently changes in paleotopography. This presentation will focuses on the MIS31 interglacial and the oceanic response to WAIS topography and Orbital forcing.

A coupled model, referred to as ICTP-CGCM, is applied to disentangle individual air-sea exchange processes driven by those forcings. The ICTP-CGCM is an useful tool to evaluate large-scale mechanism associated with interhemispheric coupling and full ocean dynamics, including for instance, a better representation of atmospheric and oceanic heat transport

Initial results demonstrated that the orbital and topography forcing acting in distinct manner. Where the topography forcing leads to cool (warm) the Northern (Southern) Hemisphere the orbital forcing delivers reversed response. As compared to the present day climate, the introduction of both forcings in the ICTP-CGCM model results in weaker rate of the North Atlantic Deep Water formation and subequently reduced Atlantic northward oceanic heat transport. It should be noted that the anomalous pattern of SST as simulated by the topography forcing simulation resembles many aspects of the interhemispheric seesaw mechanisms.

This study is supported by FAPEMIG Grant 551-13 and CNPq 407681.