In the last decades, the global climate system shows evidences of rapid change. This change is amplified in the Arctic, which is more sensitive to climate variations as they strongly affect sea ice, both on its spatial and temporal extension and on its thickness. Changes on sea ice create more melting and, consequently, change freshwater fluxes in the Arctic. These changes affect to key climate variables as well as to marine productivity. Sea Surface Salinity (SSS) is a key indicator of the freshwater fluxes and an actively sought variable, but the Arctic is a region particularly sparse in salinity in-situ measurements. For this reason, remote sensing salinity measures (currently provided by L-band satellites SMOS and SMAP) are of special relevance for this region. The computation of SSS in the Arctic represents a challenge, because brightness temperature measured by L-band satellites are less sensitive to salinity in cold waters. An additional drawback consists in the presence of sea ice in the Arctic ocean, that contaminate the brightness temperature and must be adequately processed. ESA launched in 2016 the Arctic+ initiative to support the development of novel Earth Observation based products, to reinforce the scientific component of the ESA Living Planet programme and to prepare a scientific basis for supporting activities addressing the priorities of the Arctic scientific community, including Arctic+ Snow, Arctic+ Ice, Arctic+ ArcFlux, Arctic+ YOPP and Arctic+ Salinity. The kick-off meeting of Arctic+ Salinity took place in Paris past November 7. The first task of the project is the identification of the datasets and models and the identification of test areas. Besides, new salinity retrieval algorithms and methods will be developed, in order to impove the quality of the products. Finally, SSS for the full SMOS period will be generated. One of the objectives of the project is to provide SSS products from SMOS (Level 3) and from the merging of SMOS and SMAP (Level 4). To ensure and assess the quality of the products, an intensive validation activity is intended. Finally, SSS data will be assimilated by TOPAZ4 model stablishing the scientific analysis and impact assessment, with the goal of impacting Copernicus Marine Service. In this presentation, we will present the up-to-date SSS products of the Arctic and discuss its impact for oceanographic and climate studies

2019 Living Planet Symposium, 13-17 May 2019, Milan, Italy