MSG/SEVIRI -- Brightness Temperature (BT)
The parameters to convert radiance count to radiance: gain and offset.
Radiance = count * gain+ offset
McIDAS system got these parameters from EUMETSAT.
The parameters to convert radiance to Brightness Temperature: c1w3, c2w, alpha, beta.
BT = (c2w/alog(1.0+ c1w3/radiance)- beta)/alpha
They are inserted by McIDAS code when reading data from McIDAS database. As instructed by McIDAS help desk, please use McIDAS 2007b or later version.
BT can also be obtained using the Look Up Table (LUT) created and suggested by EUMESAT. The difference between BT derived from LUT and Planck Equation is shown as below.