Six years of SMOS operations at Barcelona Expert Center: the challenge of retrieving Sea Surface Salinity from space. A tribute to Jordi Font's task

XXXII Trobades Científiques de la Mediterrània, Planeta Oceà - Planet Ocean, celebradas del 5 al 7 de octubre de 2016 en Maó, Menorca.-- Homenatge als Drs. Marta Estrada, Jordi Font i Jordi Salat, pioners de l'oceanografia mediterrània moderna. A tribute to Drs. Marta Estrada, Jordi Font and Jordi Salat, pioneers of modern Mediterranean oceanography.-- 1 pageThe ocean component of ESA Soil Moisture and Ocean Salinity (SMOS) mission represented an unprecedented challenge both from the engineering and the oceanographic point of view. SMOS target ocean variable, Sea Surface Salinity (SSS), is an Essential Climate Variable and a key component of the global water cycle. Measuring the salinity from a satellite platform requires an instrument sensitive to changes in the conductivity of sea water, what constrained engineers to work with a radiometer operating in a particular range (L‐band) of the electromagnetic spectrum. The use of L‐band implied to develop a new instrument, a radiometric interferometer known as MIRAS, with a complicated design and a sophisticated processing chain. Soon after the launch, many processing issues become evident, as the presence of systematic antenna patterns, the strong effect by Radio Frequency Interferences, a pervading Land‐Sea Contamination effect, etc. In addition, many geophysical processes were not well known until the onset of SMOS operations, as for instance the role of sea surface roughness on the emissivity of sea water, the influence of strong winds or cold water on the dielectric constant, the effect of Sun or galaxy glints, etc. After six year of operations many progresses have been made in the understanding and the processing of MIRAS, but also in the oceanographic exploitation of SMOS data. The Barcelona Expert Center, a joint venture of CSIC and UPC founded by Jordi Font, has played a very active role in that improvement of SMOS data and in the yet expanding range of applications. Under prof. Font's guidance, BEC has not only contributed to the improvement of the processing of SMOS radiometric signal, but also has opened many new (some of them, unexpected) applications: from the study of SSS in the Mediterranean at spatial and time scales deemed as unreachable by design, to the analysis of river discharges or the role of SSS in the Arctic, from the impact of high‐winds to the evaluation of the properties of sea ice. In this presentation we will review the main achievements by SMOS, and will take a glimpse on the future, on Jordi Font's legacyPeer Reviewe