ESSIC/CISESS Scientist Hu “Tiger” Yang has a new article on the Advanced Technology Microwave Sounder (ATMS) in press at IEEE Transactions on Geoscience and Remote Sensing. The Advanced Technology Microwave Sounder (ATMS) is a passive microwave radiometer for the current generation of polar-orbiting meteorological satellites operated by NOAA. The first two ATMS instruments are onboard the Suomi National Polar-orbiting Partnership (S-NPP) and NOAA-20 satellites. The article explains several critical changes in the ATMS operational calibration algorithm since March 2017. Details of the radiance-based ATMS on-orbit calibration are documented and results of pre-launch calibration error budget analysis and post-launch calibration accuracy evaluation are also presented.