Calibration comments

MSG series

The calibration of the meteosat second generation satellites is done according to the Eumetsat documents [refl], [bt].

Reflectances

The visible and near infrared channels are calibrated according to the following formula:

r = R / I

where
  • r is the bidirectional reflectance factor
  • R is the measured radiance
  • I is the solar irradiance

R is derived from the xRIT data, and I is given in [refl].

In [refl] the additional following corrections are applied:
  • sun-earth distance correction
  • cosine of the solar zenith angle.
[refl](1, 2, 3) “Conversion from radiances to reflectances for SEVIRI warm channels” EUM/MET/TEN/12/0332
[bt]“The Conversion from Effective Radiances to Equivalent Brightness Temperatures” EUM/MET/TEN/11/0569