Spatial and temporal scales of sea surface salinity variability in the Atlantic Ocean

Space-time variability of SSS in the Atlantic Ocean (33 degrees S-80 degrees N) is analyzed using near-surface salinity observations from the period 1980-2013 jointly with the output from an eddy-resolving numerical ocean simulation. Results show a good agreement between in situ and model results in terms of spatial and temporal mean SSS patterns, geographically varying SSS variability, and spatial and temporal scales of SSS variability. A good agreement exists also for estimates of the amplitude and phase of the annual cycle of SSS with the model providing more spatial details of SSS variability, which cannot be resolved by observations, especially near ocean margins and in shelf areas. Dominant spatial and temporal scales of SSS variability are, respectively, between 100 and 250 km and between 30 and 70 days in most of the Atlantic when the annual cycle of the SSS is included. However, smaller-scale salinity features are also present, which show temporal decorrelation scales of only 3-5 days throughout the Atlantic. This fast variability must be considered when producing weekly averaged salinity products from satellite measurements.