Ice-nucleating agents in sea spray aerosol identified and quantified with a holistic multimodal freezing model

Peter A Alpert; Wendy P Kilthau; Rachel E O'Brien; Ryan C Moffet; Mary K Gilles; Bingbing Wang; Alexander Laskin; Josephine Y Aller; Daniel A Knopf

doi:10.1126/sciadv.abq6842

Ice-nucleating agents in sea spray aerosol identified and quantified with a holistic multimodal freezing model

Sci Adv. 2022 Nov 4;8(44):eabq6842. doi: 10.1126/sciadv.abq6842. Epub 2022 Nov 2.

Authors

Peter A Alpert^{1

2}, Wendy P Kilthau², Rachel E O'Brien^{3

4

5}, Ryan C Moffet^{6

7}, Mary K Gilles³, Bingbing Wang^{8

9}, Alexander Laskin^{8

10}, Josephine Y Aller², Daniel A Knopf²

Affiliations

¹ Paul Scherrer Institute, Laboratory for Environmental Chemistry, 5232 Villigen, Switzerland.
² School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
³ Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
⁴ Department of Chemistry, College of William & Mary, Williamsburg, VA 23185, USA.
⁵ Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
⁶ Department of Chemistry, University of the Pacific, Stockton, CA 95211, USA.
⁷ Sonoma Technology, Petaluma, CA 94954, USA.
⁸ W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
⁹ State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
¹⁰ Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.

Abstract

Sea spray aerosol (SSA) is a widely recognized important source of ice-nucleating particles (INPs) in the atmosphere. However, composition-specific identification, nucleation processes, and ice nucleation rates of SSA-INPs have not been well constrained. Microspectroscopic characterization of ambient and laboratory-generated SSA confirms that water-borne exudates from planktonic microorganisms composed of a mixture of proteinaceous and polysaccharidic compounds act as ice-nucleating agents (INAs). These data and data from previously published mesocosm and wave channel studies are subsequently used to further develop the stochastic freezing model (SFM) producing ice nucleation rate coefficients for SSA-INPs. The SFM simultaneously predicts immersion freezing and deposition and homogeneous ice nucleation by SSA particles under tropospheric conditions. Predicted INP concentrations agree with ambient and laboratory measurements. In addition, this holistic freezing model is independent of the source and exact composition of the SSA particles, making it well suited for implementation in cloud and climate models.