SST also reads other satellite and sensor-specific data from the file, sstnoaxx.dat, where xx is the satellite number. The first few lines contain the coefficients used to compute the internal target temperature, followed by the McClain coefficients (to correct for atmospheric effects). These coefficients are followed by the information for each AVHRR thermal channel.
SST computes the GAIN and the INTERCEPT for each thermal channel in order to obtain a correspondence between grey level values and radiance. Once this table of grey level-to-radiance mappings is created, the radiances are transformed to temperatures using the inverse Planck function and then corrected for the non-linearity of the sensor. Afterwards, if the input data are 8-bit, the 10-bit information is compressed to 8-bit with the LUTs obtained from the input file's AVHRRSEG text segment.