Vertical column integrated liquid water, Liquid Water Path (LWP), is retrieved from the 89 GHz channel of MiRAC (Microwave Radar/radiometer for Arctic Clouds). MiRAC is flown with 25deg inclination backward from nadir against flight direction on Polar 5, the research aircraft of the Alfred-Wegener Institute for polar and ocean research (AWI). Polar 5 flew during the campaign Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) in summer 2017 conducted from Longyearbyen/Svalbard.The data set was collected during approximately 12 flight hours in May/June 2017 northwest of Svalbard over the sea-ice-free Arctic Ocean. It contains retrieved LWP with a status-flag indicating sea ice/sea ice floes, land, sensor inaccuracies, flight position depending on pitch and roll angle, and flight altitude. The data set is completed by information recorded by the aircraft system (latitude, longitude, flight altitude) and is stored in netCDF format.

ACLOUD campaign: Wendisch et al. 2019 (https://doi.org/10.1175/BAMS-D-18-0072.1).Instrumentation: Ehrlich et al. 2019 (https://doi.org/10.5194/essd-11-1853-2019)MiRAC: Mech et al. 2019 (https://doi.org/10.5194/amt-12-5019-2019)LWP retrieval method: Donoso et al. 2020 (https://doi.org/10.5194/acp-20-5487-2020)Data analysis: Kliesch et al. 2021 (in preparation)