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Ocean Salinity Stratification during the 2002-2012 Period as Derived from the ISA13 Argo Atlas (Poster)
[23-May-17] Maes, C., Kolodziejczyk, N., Prigent, A., and Gaillard, F.
Presented at the Global Ocean Salinity and the Water Cycle Workshop
Among the different physical processes contributing to the present climate changes and their impact on the ocean productivity and marine ecosystems, little attention has been paid to the large-scale contributions of stratification changes within the water column. Stratification, which is associated with the density difference between the surface and the deeper layers, characterizes the stability of the water column, and therefore influences the potential for vertical exchange of properties such as nutrients or dissolved oxygen. Due to the lack of in situ observations the salinity effect on stratification has often been neglected as compared to its thermal counterpart. Consequently, the differential effect resulting from the atmospheric forcing in terms of the temperature and salinity variability remains mainly unexplored. Rather than focusing on the classical halocline vs. thermocline definitions, the present study takes into account the respective thermal and saline dependencies in the Brunt-Vaisala frequency (N2) in order to isolate the specific role of the salinity stratification in the layers including the main permanent pycnocline. The role of salinity is differentiated through its stabilizing or destabilizing effect on stratification along the water column. The Ocean Salinity Stratification (OSS, as defined by Maes and O’Kane, JGR 2014) is derived from monthly gridded temperature and salinity fields (0-2000m) based on the Argo measurements (ISAS-13 temperature and salinity gridded fields, Pôle Océan, http://doi.org/z77, F. Gaillard, 2016) and is analyzed in terms of large-scale variability patterns on seasonal to interannual time scales during the 2002–2012 period.

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