Chemical characterization of sub-micrometer marine aerosol around the Ross Sea during CAIAC (2022-23 Antarctic summer)
- 1National Research Council of Italy (CNR), Institute of Atmospheric Sciences and Climate (ISAC), Bologna, Italy
- 2University of Milano Bicocca, Department of earth and environmental sciences, Milan, Italy
- 3National Research Council of Italy (CNR), Institute of Polar Sciences (ISP), Bologna, Italy
Remote from most human influences, the Southern Ocean (SO) is one of the most pristine regions on Earth and a window to preindustrial atmospheric conditions (Hamilton, 2015). Currently, many unknowns remain about atmospheric and oceanographic processes in this region and their relations. This is largely due to the poor understanding of aerosol sources and processes in this region.
Sub-micrometer aerosol samples were collected onboard the Italian RV Laura Bassi cruising the Southern Ocean and the Ross Sea, in the framework of the PNRA (Programma Nazionale di Ricerca in Antartide) project CAIAC (oCean Atmosphere Interactions in the Antarctic regions and Convergence latitude). The aim is to characterize the marine aerosol chemical composition in different ecoregions, with a particular interest for organic aerosols and their formation processes in relation with the patterns of oceanic biological activity.
Samples were collected by a high volume sampler (TECORA, ECHO-HIVOL, 500 LMP) from mid-January to mid-February 2023, deploying a wind direction selection system to avoid ship contaminations. A total of 9 samples were collected. The samples have been analysed for their water-soluble Carbon and Nitrogen content by a C-N elemental analyzer (Shimadzu) and for the ionic composition (including low molecular weight acids and amines) by ion chromatography (Dionex). The characterization of the water-soluble organic fraction in terms of tracers and functional group abundance was performed by 1H NMR (Proton Nuclear Magnetic Resonance) spectroscopy (Decesari et al, 2020).
The samples show variable contributions in terms of primary and secondary components, mostly depending on back trajectory origin and wind speed, with a general predominance of secondary species. Sulfate resulted generally the most abundant aerosol component, while water soluble organic matter (WSOM) showed a non-negligible contribution from 5 to 14% of the analysed mass. NMR spectra show the complexity of the WSOM composition, even though all the spectra were dominated by the MSA signal, which contribution in terms of carbon to WSOM spans from 8 to 64%.
Analysis of organic aerosol sources is in progress by back-trajectory analysis and statistical analysis of the NMR spectra.
Acknowledgements: CAIAC (oCean Atmosphere Interactions in the Antarctic regions and Convergence latitude) PNRA project.
Decesari, S. et al. (2020), Atmos. Chem. Phys., 20, 4193–4207, https://doi.org/10.5194/acp-20-4193-2020
Hamilton, D. S. Weather 2015, 70 (9), 264– 8, DOI: 10.1002/wea.2540
How to cite: Rinaldi, M., Paglione, M., Rapuano, M., Fellin, D., Decesari, S., Losi, N., Ferrero, L., and Lupi, A.: Chemical characterization of sub-micrometer marine aerosol around the Ross Sea during CAIAC (2022-23 Antarctic summer), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15271, https://doi.org/10.5194/egusphere-egu24-15271, 2024.
