Assessment on brightness temperature linear calibration for multi-band microwave radiometers

The method of two-point calibration of multi-band microwave radiometer is investigated in this paper. The radiometer calibration results are verified with synchronized measurements, compared between the thermometer and the calibrated radiometer for the 6.6GHz, 13.9GHz, 19.35GHz, 22.235GHz and 37GHz bands. Results show that the root-mean-square error is below 0.5K in each channel for both brightness temperature measured by radiometer and the temperature from thermometer. Therefore, assuming good radiometer receiver linearity, the calibration coefficient of radiometer obtained by two-point calibration is valid in the dynamic range of measurement. The error induced by parameter variation and the system error have been analyzed. Absolute calibration accuracy of brightness temperature is better than 1K within the radiometer measuring range.