The CCRR datasets structured as follows:A) The Match-up dataset (=match-up field + MERIS data)A-1) The match-up field datasetThe match-up field data for a site 'SiteX' (see complete list of CoactColour sites in Fig. A-1) are stored in csv files named following the classification of the parameters given in Table A-1:1) SiteX_metadata.csv including the metadata and flags,2) SiteX_biogeochem.csv including the concentrations of the biogeochemical measurements,3) SiteX_iops.csv with the inherent optical properties, and4) SiteX_aops.csv which includes the apparent optical properties.For the North Sea region, two files are provided, having the names "North_Sea" and “North_Sea_Emeco” related to the origin of the data: the North_Sea_Emeco data were downloaded from the EMECO website and North_Sea data from other Data Providers.The match-up field dataset are stored under the directory "Match-up_Dataset/FieldData/"A-2) MERIS L2 match-up productsMERIS Level 2 match-up products provided at 5x5 pixels box around the match-up locations. The data is provided as csv files, with the headers as listed in Table A-2. The MERIS 5x5 match-up data are stored under the directory "Match-up_Dataset/MERIS_5x5_L2R".A-3) MERIS averaged L2 productsThe MERIS Level 2 match-up products are further averaged over each 5x5 pixels box, discarding low quality pixels, yielding mean values of L2 products and their standard deviations. These data are also provided in csv format, with the headers as listed in Table A-3.The MERIS box-averaged L2 products are stored under the directory "Match-up_Dataset/MERIS_average_L2R".B) The in situ reflectance datasetThe in situ reflectance data are given in one csv file, listing for each Data Provider (in the first column) the sample number, the date, start and end of measurement time, latitude, longitude, the site identification number, the name of the location, the RLw spectra (9 columns for the 9 MERIS selected bands), and CHL and TSM concentrations.These data are stored under directory "InSituReflectance_Dataset".C) The simulated datasetThe simulated data are written in ascii file format. The concentrations of CHL, MP and ag(443) are given in a separate file (named “Conc.txt”) where the simulation numbers going from 1 to 5000 are listed in the first column. Each entry (e.g. each simulation number or line) is associated with a given combination of CHL, MP and ag(443)).The IOPs modelled for each entry, being the total absorption, scattering and backscattering coefficients excluding the pure water contributions, namely atot, btot, bbtot, the absorption by phytoplankton pigments, aphy, and the ratio of the total backscattering coefficient to the sum of the total absorption and backscattering coefficients bb /(a+ bb), are provided in ascii files called SPC_Atot.dat, SPC_Btot.dat, SPC_BBtot.data, SPC_Aphy.data and SPC_BBoABB.dat respectively.The simulations generated hyperspectral outputs (from 350 nm to 900 nm, with a 5 nm step), and multispectral outputs at three sensors band centered wavelengths (MODIS-Aqua, MERIS and SeaWiFS), which are specified in the prefix of the output filename SPC=“hyper”, “maqua”, “meris” or “swifs”. The three sun zenith angles (x=0, 40 and 60°), assumed successively for the set of the 5000 simulations are given in the output AOPs file names as suffixes “_szax.dat”. Separate files are provided for RLw and Kd, stored as SPC_RLw_szax.dat and SPC_Kd_szax.dat respectively. The column entry in the spectral data files gives the wavelength (in nm) and the line entry the simulation number.The simulated data also include also the photosynthetically available radiation PAREd and PAREo defined as the integration over 400 nm to 700 nm of the spectral downwelling irradiance Ed and of the scalar irradiance Eo respectively. PAREd and PAREo were profiled from 0 m above the water surface down to 80 m depth, at 27 depths listed along the columns (the line entry is related to the simulation number). The euphotic depths, ZeuEd and ZeuEo defined as the depths where PAREd and PAREo have 1% of their respective values at the water surface are provided in the files called Zeu_from_PAR_Ed_szax.dat and Zeu_from_PAR_Eo_szax.dat respectively.The concentrations, IOP and AOP spectral data, PAR and Zeu data files include headers to facilitate reading the data. The IOPs and concentration files are stored under the subfolder “Input IOPs Concentrations” and the simulated RLw, Kd, PAREd, PAREo ZeuEd and ZeuEo under “Output AOPs”.The simulated dataset files are stored under directory "Simulated_Dataset"