Two Decades of the Atlantic Meridional Overturning Circulation:

6 The zonally integrated meridional volume transport in the North Atlantic (called AMOC) 7 is described in a 19-year long ocean state estimate, one consistent with a diverse global data 8 set. Apart from a weak increasing trend at high northern latitudes, the AMOC appears 9 statistically stable over the last 19 years with fluctuations indistinguishable from those of 10 a stationary Gaussian stochastic process. This characterization makes it possible to study, 11 using highly developed tools, extreme values, predictability, and the statistical significance 12 of apparent trends. Gaussian behavior is consistent with the central limit theorem for a 13 process arising from numerous independent disturbances. In this case, generators include 14 internal instabilities, changes in the wind and buoyancy forcing fields, boundary waves, Gulf 15 Stream and deep western boundary current transports, the interior fraction in Sverdrup 16