Number concentrations of ice nucleating particles (N(INP)) in the Arctic were derived from ground-based filter samples. Examined samples had been collected in Alert (Nunavut, Northern Canadian Archipelago on Ellesmere Island), Utqiagvik, formerly known as Barrow (Alaska), Ny Ålesund (Svalbard) and at the Villum Research Station (VRS, North Greenland). For the former two stations, examined filters span a full yearly cycle. For VRS, 10 weekly samples, mostly from different month of one year, were included. Samples from Ny Ålesund were collected during the months from March until September of one year. Given here are background information on the filter samples, the temperature dependent measured frozen fractions together with N(INP) and one file containing the frozen fractions determined for the field blank filters (see at “Further details” below).

Supplement to: Wex, Heike; Huang, Lin; Zhang, W; Hung, Hayley; Traversi, Rita; Becagli, Silvia; Sheesley, Rebecca; Moffett, James; Barrett, T E; Bossi, Rossana; Skov, Henrik; Hünerbein, Anja; Lubitz, Jasmin; Löffler, M; Linke, O; Hartmann, Markus; Herenz, Paul; Stratmann, Frank (2019): Annual variability of ice-nucleating particle concentrations at different Arctic locations. Atmospheric Chemistry and Physics, 19(7), 5293-5311