Document Type

Article

Publication Date

10-16-2026

Department

Department of Physics

Abstract

Atmospheric dust is a primary source of ice nucleating particles (INPs), yet their concentrations at temperatures warmer than −20°C are not fully characterized during Asian dust events. This study uses a membrane filtering method to collect aerosol samples and a droplet freezing method to measure daily immersion-mode INP concentrations in Beijing during the dust season throughout March 2022. Daily aerosol samples are categorized into low, moderate, and heavy dust conditions using volume depolarization ratios from a Micro Pulse Lidar (MPL). Observed INP spectra exhibit a day-to-day variability of up to two orders of magnitude at a given temperature. The INP spectra can generally be fitted with a two-mode distribution. We find that INP concentration correlates strongly with the mass concentration of coarse aerosols (PMcoarse), but weakly with that of fine aerosols. We therefore develop a PMcoarse-based INP parameterization that is applicable to the mixed-phase cloud temperature range (−3.5°C to −23.5°C). The parameterization scheme is validated using several independent measurements in the Beijing region. It offers a practical approach for estimating INP concentrations at relatively warm temperatures in atmospheric models by utilizing routinely available PMcoarse data from air-quality monitoring networks or chemical transport models. Heat treatment tests reveal that more than 50% of INPs are heat-sensitive, indicating that biological or other heat-sensitive materials may significantly contribute to INP concentrations, particularly at warmer temperatures.

Publisher's Statement

© 2026 The Author(s). Journal of Geophysical Research: Atmospheres published by Wiley Periodicals LLC on behalf of American Geophysical Union. Publisher’s version of record: https://doi.org/10.1029/2026JD046632

Publication Title

Journal of Geophysical Research Atmospheres

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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