Using Argo data to investigate the MOC in the North Atlantic

This is a summary of the paper "Using Argo data to investigate the MOC in the North Atlantic" for the EuroArgo platform in order to show the possible uses of data from ARGO profilers by the scientific community. The original authors are contained in the review. Through the poleward transport of upper ocean waters and an equatorward transport of deeper colder waters, the Meridional Overturning Circulation (MOC) is of critical importance to the global climate system. A decline of the MOC has been one of the predictions of various IPCC reports on greenhouse gas scenarios (IPCC,2001), and a particular aspect of recent findings from a single hydrographic section at 24°N in 2004 is that more equatorward flow is found in the interior of the upper 1000 meters than previously observed. To check the robustness of this recent result, the North Atlantic MOC has been studied here (Hernandez-Guerra, 2010) through the analysis of hydrographic data along 24o and 36o N. Results confirm previous hypothesis stating no abrupt decreases in the MOC during the last decades, by comparing 1957, 1981,1992, 1998 and 2004 data. Argo float profiles and drift velocities for the period 2003-2007 in the North Atlantic are also used to estimate the total integrated mass transports in the thermocline waters at both mid-latitudes by inverse calculations. They confirm that the upper limb of the Atlantic MOC has not significantly changed since 1957