On the response of Southern Ocean water-masses to atmospheric meridional moisture advection

[1] We investigate the role of atmospheric moisture advection in determining Southern Ocean water-mass properties in a coupled climate model. Two sensitivity experiments are presented in which the winds advecting moisture are either reduced or enhanced south of 45S. It is shown that a variation in meridional winds in the Southern Ocean can generate large anomalies of subsurface potential temperature (T) and salinity (S). A reduction (increase) in southward atmospheric moisture advection tends to be balanced by a corresponding reduction (increase) in northward freshwater transport in Antarctic Intermediate Water. The response of both T and S is larger in the case of reduced southward moisture advection, as this corresponds to an overall reduction of Southern Ocean stratification. The interior ocean T–S response is not always density-compensating, particularly in the Indian and Pacific Oceans. This is unlike zonal wind variations which have a tendency to change T–S in a density-conserving manner. Our study suggests that variability in meridional winds over the Southern Ocean can alter local water-mass formation rate