Direct Online Mass Spectrometry Measurements of Ice Nucleating Particles at a California Coastal Site. Issue 22 (19th November 2019)

• Record Type: Journal Article
• Authors: Cornwell, G. C.; McCluskey, C. S.; Levin, E. J. T.; Suski, K. J.; DeMott, P. J.; Kreidenweis, S. M.; Prather, K. A.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 22(2019)
• Page Start: 12157
• Page End: 12172
• Publication Date: 2019-11-19
• Subjects: ice‐nucleating particles -- aerosol time‐of‐flight mass spectrometry -- dust; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2019JD030466
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: The formation of ice in clouds can strongly impact cloud properties and precipitation processes during storms, including atmospheric rivers. Sea spray aerosol (SSA) particles are relatively inefficient as ice nucleating particles (INPs) compared to mineral dust. However, due to the vast coverage of the Earth's surface by the oceans, a number of recent studies have focused on identifying sources of marine INPs, particularly in regions lacking a strong influence from dust. This study describes the integration, validation, and application of a system coupling a continuous flow diffusion chamber with a single particle mass spectrometer using a pumped counterflow virtual impactor to remove nonnucleated particles and selectively measure the composition of INPs with a detection efficiency of 3.10 × 10 −4 . In situ measurements of immersion freezing INP composition were made at a coastal site in California using the integrated system. Mineral dust particles were the most abundant ice crystal residual type during the sampling period and found to be ice active despite having undergone atmospheric processing. SSA were more abundant in ambient measurements but represented only a minor fraction of the ice crystal residual population at −31 °C. Notably, the SSA particles that activated were enriched with organic nitrogen species that were likely transferred from the ocean. Calculations of ice nucleation active site densities were within good agreement with previous studies of mineral dust and SSA. Key Points: The most abundant immersion freezing ice nucleating particle type (T = −30 °C) was mineral dust during a week‐long study at a coastal site Nitrate content made little difference to the ice nucleation activity of dust Sea spray aerosol that formed ice crystals were enriched in organic nitrogen species