The major goal of this working group is to improve understanding of the link between L-band satellite (SMOS, SMAP and Aquarius) remotely sensed salinity (1cm depth, 50-150km resolution), and in situ measured salinity and to develop practical methodologies for relating various estimates of sea surface salinity (SSS). During this splinter, we will discuss SSS horizontal and vertical variability within satellite pixels and between 1cm and a few meters depths as derived from recent in situ measurement campaigns and models, as well as their consequences for satellite SSS validation. We will also take this opportunity to prepare what could be presented during the 2020 Ocean Salinity Science conference foreseen in Fall 2020 in the US. Please contact J. Boutin (jb@locean-ipsl.upmc.fr) and Nadya Vinogradova(nadya@nasa.gov) if you'd like to participate to this splinter.