Enhanced warm-temperature marine ice-nucleating particles over the Arctic Ocean versus Asian-dust outflow at Jeju Island from real-time shipborne observations

Abstract. Ice-nucleating particles (INPs) influence mixed-phase cloud microphysics and the Earth’s radiative budget, yet observational records over the remote Arctic Ocean and contrasting continental-outflow environments remain sparse. This study presents INP concentrations measured by the Portable Ice Nucleation Experiment (PINE) over the Arctic Ocean during two RV(Research Vessel) Araon campaigns (ARA15A in 2024 and ARA16A in 2025) and at the Korea-Cloud Physics Experiment Chamber (K-CPEC) on Jeju Island, Korea (February–May 2024), totalling 41,524 expansion runs of which 35,370 passed rigorous quality control. INP temperature spectra differed markedly among the three datasets. At a representative warm temperature (−20 °C), median concentrations were 3.68 L⁻¹ (ARA15A), 3.64 L⁻¹ (ARA16A), and 0.89 L⁻¹ at Jeju (Clean-day subset), with Arctic values exceeding Jeju; at a representative cold temperature (−28 °C), the pattern reversed — the Jeju Clean-day median rose to 8.22 L⁻¹ while Arctic medians remained comparatively flat (ARA15A: 7.02 L⁻¹; ARA16A: 6.39 L⁻¹). Campaign-wide medians were comparable between the two Arctic years (6.83 and 6.57 L⁻¹) but differed approximately two-fold in the 75–80° N latitude band (ARA15A: 1.56 and ARA16A: 3.19 L⁻¹). These spectral contrasts are consistent with a marine biogenic-influenced regime at the Arctic warm-temperature end and an Asian-dust-influenced regime at the Jeju cold-temperature end, although direct compositional confirmation (heat treatment, chemical speciation) was not available in this dataset; all source attributions should therefore be interpreted as spectrally-consistent hypotheses rather than established source identifications. A dedicated ship-exhaust quality control scheme applied to both campaigns provides a replicable contamination-removal framework for future shipborne INP studies, and the combined dataset delivers new observational benchmarks for Arctic INP variability across the sampled 2024–2025 cruise periods.