The data set contains measurements performed by the passive radiometer Humidity And Temperature PROfiler (HATPRO; Rose et al., 2005) operated on board the Polar 5 research aircraft during 9 flights of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Airborne observations in the Central Arctic (MOSAiC-ACA; Mech et al., 2022) campaign, carried out in late summer 2020 northwest of Svalbard (Norway). The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3. The published data set consists of brightness temperature measurements at nadir view with respect to the aircraft's fuselage at seven frequencies in the 22.24 GHz water vapor absorption band and seven at the 60 GHz oxygen absorption complex. It should be considered that the brightness temperatures have not been corrected for aircraft attitude. The data set has been quality-checked and is available in NetCDF format for each flight separately.Details on the dataset and its usage can be found in Mech et al. (2022).