From the three processing modes of the OLCI Level-1 processor (Earth Observation (EO), Radiometric Calibration (RC) and Spectral Calibration (SC)) and the two available Resolutions in EO (Full and Reduced Resolution), four different Level-1B products can be obtained:

• OL_1_EFR, output during EO processing mode for Full Resolution
• OL_1_ERR, output during EO processing mode for Reduced Resolution
• OL_1_RAC, output during Radiometric Calibration mode
• OL_1_SPC, output during Spectral Calibration mode

NOTE: OL_1_RAC and OL_1_SPC are internal PDGS products, and not disseminated to SENTINEL-3 users.

The Level-1B products in EO processing mode contain calibrated, ortho-geolocated and spatially re-gridded Top Of Atmosphere (TOA) radiances for the 21 OLCI spectral bands. The associated error estimates are also contained in the measurement data files. In Full Resolution products (i.e. at native instrument spatial resolution), these parameters are provided for each re-gridded pixel on the product image and for each removed pixel. In Reduced Resolution products (i.e. at a resolution four times coarser), the parameters are only provided on the product grid.

In addition to measurement datasets, annotation datasets provide:

• time stamps for each line of the product grid
• geolocation information for each pixel (and for each removed pixel in case of OL_1_EFR)
• quality flags, concerning surface or cloud identification, invalid or cosmetically filled pixels
• meteorological variables for each tie-point (defined on a specific grid: every 16 pixels for RR and every 64 pixels for FR products)
• geographical information and angles associated with each tie-point
• instrument features and settings needed in further processing such as detector index or OLCI channels, central wavelength and bandwidths.