The data set contains measurements performed by the passive radiometer Humidity and And Temperature PROfiler (HATPRO) operated on board the Polar 5 research aircraft during 10 flights of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Airborne observations in the Central Arctic (MOSAiC-ACA) 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 aircrafts 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 considerd, 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.

The files contain brightness temperatures, measurement times, and some key numbers of the operated instrument. In addition meta information and attributes are provided. The files are in netcdf format following CF-1.8.