The visible and near infrared channels are calibrated according to the following formula:
r = R / I
- 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