Retrieved specific humidity (q) from microwave radiometer measurements during the MOSAiC expedition

This data set contains daily files of temperature (temp), specific humidity (q) and relative humidity (rh) profiles derived from combined measurements of the HATPRO and MiRAC-P microwave radiometers (see Walbröl et al. 2022, https://doi.org/10.1038/s41597-022-01504-1) operated aboard the Polarstern during cruise PS122 (MOSAiC expedition). The data covers the time range from 22 October 2019 until 02 October 2020 with a temporal resolution of about 1 second (except for temp_bl data, see below). Both microwave radiometers were mounted on top of the OCEANET-ATMOSPHERE container (Macke et al. 2010, https://doi.org/10.1051/epjconf/201009006; Engelmann et al. 2021, https://doi.org/10.5194/acp-21-13397-2021). HATPRO is a Humidity and Temperature Profiler (Rose et al. 2005, https://doi.org/10.1016/j.atmosres.2004.12.005) that measures atmospheric radiation emitted from water vapour along a rotational water vapour aborption line in the K-band (7 channels from 22.24 to 31.4 GHz) and from oxygen along the absorption complex in the V-band (7 channels from 51.26 to 58 GHz). The HATPRO measurements are also sensitive to radiation emitted from hydrometeors (cloud liquid water). MiRAC-P is a Low Humidity Profiler (LHUMPRO-243-340, Mech et al. 2019, https://doi.org/10.5194/amt-12-5019-2019), also known as the Microwave Radiometer for Arctic Clouds - Passive, that measures atmospheric radiation at higher frequencies along a strong water vapour absorption line in the G-band (6 channels from 183.31 +/- 0.6 to 183.31 +/- 7.5 GHz), and in the window channels (no distinct absorption lines) 243 and 340 GHz. We developed a Neural Network for each derived quantity. Because of the different water vapour sensitivities of the K-band and the G-band channels, the derived humidity profiles from combined HATPRO and MiRAC-P measurements were strongly improved compared to the HATPRO-only retrievals (see Walbröl et al. 2024; in preparation). Temperature profiles were retrieved from zenith observations using both HATPRO and MiRAC-P measurements (temp), and separately from boundary layer scans from HATPRO only (temp_bl), which were performed once every 30 minutes. Relative humidity (rh) was computed from retrieved q and temp profiles and combined with radiosonde air pressure measurements (Dahlke et al. 2023, https://doi.org/10.1594/PANGAEA.961881) that were interpolated onto the retrieval height grid and time axis. Specific humidity was retrieved until a height of 10000 m, while temperature and relative humidity profiles are limited to 0-8000 m because of the strong temperature gradient in the tropopause. Error estimates in terms of root mean squared error are provided within each file as variables (e.g., q_rmse for specific humidity). Quality flags of each instrument (flag_h for HATPRO and flag_m for MiRAC-P) are also included in each file and can be used to filter data with bad quality. The data has good quality when the flag values (flag_h and flag_m) are 0 or nan (depends on the importing routine). Additionally, data where flag_h is 32 can also be used with care.