The OLCI+SLSTR/Sentinel-3A L2 Surface Reflectance and Aerosol parameters over Land product with shortname S3A_SY_2_SYN, is generated by combining data acquired by the Ocean and Land Colour Instrument (OLCI) and the Sea and Land Surface Temperature Radiometer (SLSTR), on-board SENTINEL-3. The OLCI is a push-broom imaging spectrometer that measures solar radiation reflected by the Earth at a ground spatial resolution of around 300m, over all surfaces, in 21 spectral bands whereas the SLSTR is a dual scan temperature radiometer. The principal objective of SLSTR products is to provide global and regional Sea and Land Surface Temperature (SST, LST) to a very high level of accuracy (better than 0.3 K) for both climatological and meteorological applications. For more information about the instrument and the mission, visit "Sentinel Online" at https://sentinel.esa.int/web/sentinel/home. The S3A_SY_2_SYN is a Level 2 product which consist of surface reflectances for all SYN channels and aerosol parameters over Land. There are 29 Measurement Data Files and 9 Annotation Data Files included in this product. All measurement datasets are provided on the OLCI image grid, similar to the one included in the OLCI L1b product. For more information about the product, read the SENTINEL-3 Synergy User Guide at https://sentinel.esa.int/web/sentinel/user-guides/sentinel-3-synergy