Partial Control of the Gulf of Mexico Dynamics by the Current Feedback to the Atmosphere

Abstract The surface oceanic Currents FeedBack to the atmosphere (CFB) has been shown to correct long-lasting biases in the representation of ocean dynamics by providing an unambiguous energy sink mechanism. However its effects on the Gulf of Mexico (GoM) oceanic circulation are not known. Here, twin ocean-atmosphere eddy rich coupled simulations, with and without CFB, are performed for the period 1993-2016 over the GoM to assess to which extent CFB modulates the GoM dynamics. CFB, through the eddy killing mechanism and the associated transfer of momentum from mesoscale currents to the atmosphere, damps the mesoscale activity by roughly 20% and alters eddy statistics. We furthermore show that the Loop Current (LC) extensions can be classified into 3 categories: a retracted LC, a canonical LC, and an elongated LC. CFB, by damping the mesoscale activity, enhance the occurrence of the elongated category (by about 7%). Finally, by increasing the LC extension, CFB plays a key role in determining LC eddy separations and statistics. Taking into account CFB improves the representation of the GoM dynamics and should be taken into account in ocean models.