Fore software (toolbox) and data of the upcoming Sentinel-3 check this website: https://sentinel.esa.int/web/sentinel/toolboxes/sentinel-3.
” The Sentinel-3 Toolbox consists of a rich set of visualisation, analysis and processing tools for the exploitation of OLCI and SLSTR data from the upcoming Sentinel-3 mission. As a multi-mission remote sensing toolbox, it also supports the ESA missions Envisat (MERIS & AATSR), ERS (ATSR), SMOS as well as third party data from MODIS (Aqua and Terra), Landsat (TM), ALOS (AVNIR & PRISM) and others. The various tools can be run from an intuitive desktop application or via a command-line interface. A rich application programming interface allows for development of plugins using Java or Python. [..]
This first release of the Sentinel-3 Toolbox is a stand-alone toolbox intended for exploitation of medium resolution optical and SMOS data. It provides all tools known from the ESA BEAM and SMOS toolboxes, plus a Sentinel-3 data reader, an uncertainty data visualisation tool and a context search feature. The next release will consist of a common Sentinel Application Platform (SNAP) for Sentinel-1, Sentinel-2 and Sentinel-3 with a single installer and application interface.”