The tethered balloon system BELUGA (Balloon-bornE moduLar Utility for profilinG the lower Atmosphere) was operated during leg 4 of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC). The balloon was operated from the Balloon Town site in the central observatory, close to RV Polarstern (Shupe et al., 2022, Elementa). Balloon payload included an extended meteorological package, an ultrasonic anemometer package, a broadband radiation package, the video ice particle sampler, and the cubic aerosol measurement platform. An overview showing the value of the combined observation is displayed by Lonardi et al. (submitted). The data processing is described in Pilz et al. (in preparation). The present dataset covers the processed terrestrial irradiances measured by the broadband radiation package on 18 flights between 29 June and 27 July 2020. Terrestrial irradiances were corrected for the time response of the pyrgeometer (6 s) and averaged over 3 s. Flagging of ice and liquid water is provided, based on the analysis of 0.1 Hz pictures of the upper pyrgeometer. Solar irradiances are also available (doi:10.1594/PANGAEA.944232).