During the legs PS106 and PS107 of the RV Polarstern, a Fourier-Transform Infrared (FTIR) spectrometer was used to measure radiation emitted by clouds. Spectra were recorded between 700 cm^-1 (14.29 micrometer) and 1200 cm^-1 (8.33 micrometer). From these spectra, the cloud optical depths and the effective droplet radii were retrieved and the liquid water path (LWP), ice water path (IWP) and the condensed water path (CWP=IWP+LWP) calculated. The errors of the cloud optical depths and the effective droplet radii are the standard deviations of the retrieval, from which the errors of LWP, IWP and CWP were calculated. The averaging kernel matrices describe the sensitivity of the retrieval to the parameters.Cloud base heights were taken from the Polarstern ceilometer CL51. See also:Ceilometer CL51 raw data:https://doi.pangaea.de/10.1594/PANGAEA.883320https://doi.pangaea.de/10.1594/PANGAEA.883322https://doi.pangaea.de/10.1594/PANGAEA.883323