Ice Nucleating Particle number concentration over the Southern Ocean during the austral summer of 2016/2017 on board the Antarctic Circumnavigation Expedition (ACE).

<strong>Dataset abstract </strong> Ice Nucleating Particles (INP) are a subclass of atmospheric aerosol particles, which can force heterogeneous freezing of cloud droplets at temperatures above -38 degrees C. In contrast, ice particles form from cloud droplets at temperatures below -38 degrees C due to homogeneous freezing, without INP. Due to their abundance, these particles can affect micro-physical properties of clouds, while acting as INP. During the Antarctic Circumnavigation Expedition (ACE) cruise around the Southern Ocean, off-line filter sampling was performed. Filters were stored on the ship and analysed after the cruise at Leibniz-Institute for Tropospheric Research (TROPOS) concerning INP abundance. We give INP number concentrations for sampling periods of 8 hours (or 2 hours in special cases) each. <strong>Dataset contents</strong> ACESPACE_ice_nucleating_particle_number_concentration_Tminus15degC.csv, data file, comma-separated values data_file_header.txt, metadata, text format README.txt, metadata, text format For latitude and longitude NaN values are given, in cases positioning data was not available for given time period. INP number concentration values can be equal zero, indicating material sampled not being ice active at given temperature. In some cases, given INP number concentration values represent the upper detection limit of the used method.