Airborne radar reflectivity and brightness temperature measurements with POLAR 5 during ACLOUD in May and June 2017

During the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign in summer 2017 conducted from Longyearbyen/Svalbard, a combination of active and passive microwave instruments MiRAC (Microwave Radar/radiometer for Arctic Clouds) has been operated on board of the Polar 5 research aircraft of the Alfred-Wegener Institute for polar and ocean research (AWI). MiRAC contains a Frequency Modulated Continuous Wave (FMCW) radar at 94 GHz mounted in a belly pod under 25deg backwards inclined with respect to nadir. Included is also the 89 GHz passive channel and a passive microwave instrument with six channels in the 183 GHz water vapor line and channels at 243 and 340 GHz installed nadir pointing in the cabin.

The data set was collected during approximately 80 flight hours in May/June 2017 northwest of Svalbard over the Arctic ocean and sea ice. It contains the unfiltered reflectivity profiles as well as the filtered profiles. Both profiles are corrected for aircraft motion and instrument/aircraft orientation. The filters consider disturbances due to the signal processing, side lobe effects, and removal of speckles. Furthermore, quality flags for the radar reflectivity are included in the data set. For the passive component, the brightness temperatures at 89 GHz are included without considering the observation geometry. The data set is completed by information recorded by the aircraft system (latitude, longitude, flight height, pitch, roll, and flight speed). The data are stored as netCDF format and each file contains data for one research flight (except for the 17th and 23rd of June 2017). For the higher passive microwave channels a separate dataset will be provided.

For detailed information on the instruments and the processing see Mech et al. 2019 (doi:10.5194/amt-2019-151).

The campaign ACLOUD is described in Wendisch et al. 2018 (doi:10.1175/BAMS-D-18-0072.1).