Calibration experiments of ground-based microwave radiometers

This dataset contains data from HATPRO microwave radiometer (MWR) absolute calibrations conducted by the University of Cologne in Jülich, Germany between 2017 and 2024. Furthermore, there are data from MWR calibrations during the FESSTVaL experiment in Lindenberg, Germany. In total, four different HATPRO Generation 5 (G5) instruments have been used: TOPHAT (an upgraded G2>G5 radiometer), and JOYHAT (G5) in Jülich, as well as DWDHAT and FOGHAT for FESSTVaL (both G5). The data consist of brightness temperature observations on the cold and hot calibration target and can be used to monitor the stability and drifts of microwave radiometer receivers. FESSTVaL data were also used to assess the repeatability of absolute MWR calibrations.