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Skliris, N., Marsh, R., Josey, S.A., Liu, C.L., and Allen, R.P. (26-Feb-14)

Global hydrographic and air-sea freshwater flux datasets are used to investigate ocean salinity changes over 1950-2010 in relation to surface freshwater flux. Surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic-Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E-P are examined for 1950-2010 (using two reanalyses) and 1979-2010 (using six reanalyses/blended products). Large differences in the 1950-2010 E-P trend patterns are evident in a number of regions, particularly the North Atlantic. For 1979-2010, some coherency in the spatial patterns of change is obtained between the six products, notably a robust pattern of increased E-P in the subtropics of the southern hemisphere. The water cycle amplification over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in time-varying isopycnal volumes. Inferred changes of E-P over 1950-2010 amount to an increase of 1±0.6% in net evaporation across the subtropics and an increase of 4.2±2% in net precipitation across subpolar latitudes, while amplification rates are approximately doubled over 1979-2010.