This data set contains daily files of atmospheric (PS149_uoc_hatpro_l1_tb_v01_2025.nc) and surface (PS149_uoc_hatpro_l1_tb_sfc_v01_2025.nc) brightness temperatures measured by the Humidity And Temperature PROfiler (HATPRO, Rose et al., 2005) onboard the research vessel Polarstern during cruies PS149 from 4 July to 29 August 2025. HATPRO measures brightness temperatures at seven channels between 22.24 and 31.4 GHz (water vapour absorption line, K-band) and at seven channels between 51.26 and 58 GHz (oxygen absorption complex, V-band). The instrument was mounted at the portside railing on one of the highest decks of Polarstern (lower Peildeck).Note that the surface brightness temperature files contain observations at different zenith angles and also provide atmospheric brightness temperatures at the angle corresponding to the atmospheric signal reflected by the surface. The latter is needed for surface emissivity calculations.

Each netCDF file contains either atmospheric (PS149_uoc_hatpro_l1_tb_v01_2025.nc) or surface (PS149_uoc_hatpro_l1_tb_sfc_v01_2025.nc) brightness temperatures measured by HATPRO onboard Polarstern for one day of the cruise PS149. Each file further contains meta data about the position (latitude, longitude, height above mean sea level), the zenith angle, the quality and the frequency of the measured brightness temperature, and provides standard meteorological parameters (air temperature, pressure and relative humidity) from the weather station mounted to HATPRO.