MVIRI Level 1.5 Climate Data Record Release 1 - MFG - 57 degree

Release 1 of the Fundamental Climate Data Record (FCDR) of the Meteosat Visible and Infrared Imager (MVIRI) onboard the Meteosat First Generation (MFG) provides georectified, recalibrated, and consolidated Level 1.5 data of the visible (VIS), infrared (IR) and water vapor (WV) bands along with all metadata, spectral response functions (reconstructed for the VIS channel), as well as calibration information to compute radiance, brightness temperature and reflectance. The VIS band data are provided along with detailed measurement uncertainties and error correlation information. As further elaborated in the Product User Guide, the files are provided in FIDUCEO EASY and FULL (only available on special request) netCDF4 formats.

Release 1 of the MVIRI FCDR consists of data from the Meteosat-7 satellite with nominal sub-satellite longitude 57 degrees. Release 1 was produced as part of the FP7 ERA-CLIM2 and H2020 FIDUCEO project.

The computed “toa_bidirectional_reflectance_vis” from the recalibrated visible channel radiances are stored as unsigned short integers with a scaling factor 3.05176e-05 so that the maximum float value that can be stored in the integer of 65535 is 1.99997. BRF values of 2.0 and higher are consequently overflowing the bit depth, and are presented as valid values, lower than the maximum. For high solar angles in combination with high viewing angles, cloud tops were observed with BRF values that exceed the bit depth. They are wrongly presented as dark and cannot be distinguished from pixels that actually are dark. This will be mitigated in the release 3 of MVIRI FCDR. If users would like to circumvent this issue, they can contact EUMETSAT to obtain the FULL version of the FCDR data that contain original count values and recalibration coefficients which allow for the computation of “toa_bidirectional_reflectance_vis” without running into the aforementioned issue.