Research On Tipping-curve Calibration Method Of Ground-based Microwave Radiometer

Microwave radiometer, as a passive remote sensing instrument, is used to obtain objective information mainly basing on brightness temperature and related theory. The accuracy of the objective information depends on the accuracy of the radiometer calibration. Therefore, calibration is an important step in absolute measurements, and calibration accuracy makes a direct impact on the measurement accuracy.This thesis introduces the working principle of the microwave radiometer, a brief introduction of liquid nitrogen-the normal temperature calibration, noise injection calibration. It focuses on the tipping-curve calibration based on atmospheric transmission theory and the sky brightness temperature calculation, and proposes a tipping-curve calibration program suitable for ground-based meteorological microwave radiometer and realize it using MATLAB. We analyze the simulation of tipping-curve calibration program using the atmospheric data in WuHan from RAOB. In addition, as the lack of access to the atmospheric mean radiant temperature data in real time base on sounding ballons in the actual measurement, the paper proposes a algorithm to get the atmospheric mean radiant temperature deduced from the surface temperature.Finally, an experiment using 8 mm DICKE radiometer is made to proof the feasibility of the tipping-curve calibration program described above.