Tipping calibration for digital gain compensative microwave radiometer and correction on antenna sidelobe influences

Abstract

The tipping curve calibration method has been an important calibration technique for ground‐based microwave radiometers that measure atmospheric water vapor and cloud liquid water. The method calibrates a radiometer system using the brightness temperatures at various viewing angles in the atmosphere. In this paper, the tipping calibration was carried out by digital gain compensative microwave radiometer (DGCMR) in Inner Mongolia, China, in August 2006. The frequencies of the radiometers are 23.8 and 31.65 GHz with rectangle horn and paraboloid antenna. Using the relationship between correction value and scanning angle, the brightness temperature of the antenna sidelobe contribution is corrected. The comparison of the correction results for the two antenna types shows that the antenna sidelobe error for the rectangular horn antenna can be corrected more effectively.