Robustness of the Atlantic-Pacific flow reversal in the early miocene

Abstract. Based on modeling results and interpretations of observations, it has been suggested that during the early Miocene, a reversal of the Atlantic-Pacific ocean flow through the Panama Strait has occurred. During the Oligocene the net transport was westward, from the Atlantic into the Pacific, whereas in the Miocene the sign of this transport likely reversed to a net eastward transport into the Atlantic. With a global ocean model for the Oligocene and Miocene continental configurations we study the robustness of this flow reversal by carrying out a broad sensitivity analysis, including bottom topography, details of the continental geometry and surface forcing. This sensitivity study is efficiently done by using recent methodology to compute equilibrium solutions to the model. The Atlantic-Pacific flow reversal appears a very robust feature of the global ocean model.