This dataset contains information about the state of the central Arctic lower atmosphere during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Through the merging of MOSAiC radiosonde, 10-m meteorological tower, ceilometer, and radiation station observations, this dataset provides information about the atmospheric boundary layer (depth and stability), temperature features (near-surface temperature and temperature inversion characteristics), wind features (near-surface wind speed and low-level jet characteristics), moisture features (near-surface mixing ratio and cloud characteristics), and surface radiation budget (up- and downwelling longwave and shortwave radiative flux) at the time of each MOSAiC radiosonde launch (approximately 4 times per day between September 2019 and October 2020). The dataset is structured in a NetCDF4 file, which follows the CF-1.10 convention. The objective of this dataset is to provide the user community with a consistent description of general lower atmospheric conditions throughout the MOSAiC year.