MERIS RR Level 2 is a Reduced Resolution (RR) Geophysical product for Ocean, Land and Atmosphere. Each MERIS Level 2 geophysical product is derived from a MERIS Level 1 product and auxiliary parameter files specific to the MERIS Level 2 processing. The MERIS RR Level 2 product has Sentinel 3-like format starting from the 4th reprocessing data released to users in July 2020. The data package is composed of NetCDF 4 files containing instrumental and scientific measurements, and a Manifest file, which contains metadata information related to the description of the product. A Level 2 product is composed of 64 measurement files containing mainly: 13 files containing Water-leaving reflectance, 13 files containing Land surface reflectance and 13 files containing the TOA reflectance (for all bands except those dedicated to measurement of atmospheric gas - M11 and M15), and several files containing additional measurement on Ocean, Land and Atmospheric parameters. The Auxiliary data used are listed in the Manifest file associated to each product. MERIS was operating continuously on the day side of the Envisat orbit (descending track). RR data was acquired over 43.5 minutes in each orbit, i.e. 80% of the descending track.