Minimize Level-1

OLCI Level-1 data is divided into four product packages; two User products and two Internal products. Each product is composed of an information package map, also called a manifest, and several measurement and annotation data files.

User Products

  • OL_1_EFR, providing the OLCI Level-1 Full Resolution product, includes 22 measurement data files and seven annotation data files.
  • OL_1_ERR, providing the OLCI Level-1 Reduced Resolution product, includes 21 measurement data files and seven annotation data files.

Internal Products

  • OL_1_RAC, providing internal dark offset and gain coefficient from radiometric calibration: includes one measurement data file and one annotation data file.
  • OL_1_SPC, providing internal wavelength characterisation from spectral calibration: includes one measurement data file and two annotation data files.

For OL_1_EFR and OL_1_ERR products, the measurement files are written in netCDF 4 format and contain the TOA radiances and their error estimates for each OLCI channel.

OL_1_EFR is also composed of one file providing data for each removed pixel, the 21 associated radiances, geographical position, associated angles and flags.

The annotation data files, also written in netCDF 4 format, are similar and described in the following table.

Table 1: Description of annotation data files included in OLCI User products
File Name Dimensions Contents
timeCoordinates Number of lines in the product image Time stamp
geoCoordinates Number of lines and columns in the product image. Longitude, Latitude, Altitude
qualityFlags Number of lines and columns in the product image. Quality flags.
tie_geoCoordinates Number of lines and columns in the tie-point grid. Longitude, latitude.
tie_geometries Number of lines and columns in the tie-point grid Sun and observation angles:
Sun Zenith Angle (SZA)
Sun Azimuth Angle (SAA),
Observation Zenith Angle (OZA),
Observation Azimuth Angle (OAA)
tie_meteo Number of lines and columns in the tie-point grid.

ECMWF data:

horizontal_wind, sea_level_pressure,
total_ozone, humidity,
reference_pressure_level,
atmospheric_temperature_profile,
total_columnar_water_vapour

instrumentData Number of lines and columns in the product image, number of instrument detectors per frame and number of OLCI bands.. lambda0,
FWHM,
Solar Flux,
detector_index,
frame_offset,
relative_spectral_covariance

For calibration products, the content is similar, written in netCDF 4 and described in the following table.

 

 

Table 2: Description of OLCI Level-1 product from calibration processing
File Name Product File Type Dimensions Contents
radiometricCoef OL_1_RAC Measurement Number of instrument detectors, number of OLCI band and number of dark and blank pixels. Dark offsets and currents
coefficients; gain coefficients and time average of the dark/blank pixels acquired in shutter or diffuser position.
RC_annotations OL_1_RAC Annotation Number of instrument detectors, number of OLCI band and number of OLCI cameras. Quality flags, valid acquired
pixels used in different computation and statistics of CCD temperature in shutter or diffuser position.
calWavelengths OL_1_SPC Measurement Number of used frames, of selected row, number of instrument detectors, of OLCI camera and number of dark/blank pixels. Central wavelengths, time average of the dark/blank pixels acquired in shutter or diffuser position.
TimeCoordinates OL_1_SPC Annotation Number of used frames. Time stamps.
SC_annotations OL_1_SPC Annotation Number of used frames, of selected row, of instrument detectors and of OLCI camera. Quality flags and statistics of CCD temperature in shutter or diffuser position.

Associated with each file, an information package map describes the content unit identifier and description, and the type of data contained in each file. An XML manifest file contains metadata associated with the instrument and the processing.

The Level-1 Product Data Format Specification document contains more detailed information.