EGU26-6049, updated on 13 Mar 2026
https://doi.org/10.5194/egusphere-egu26-6049
EGU General Assembly 2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
Oral | Monday, 04 May, 16:40–16:50 (CEST)
 
Room M2
Antarctic Continental Outflow as a Transport Pathway for Elevated Gaseous MSA and Biogenically Dominated Cloud Condensation Nuclei: Insights from the MISO Voyage
Branka Miljevic1, Joel Alroe1, Marc D. Mallet2, Abithaswathi Muniraj Saraswathy1, Alain Protat3, Gerald G. Mace4, Kelsey Barber4, Sreenath Avaronthan Veettil5, Tahereh Alinejadtabrizi5, Ruhi S. Humphries6, and Sally Taylor6
Branka Miljevic et al.
  • 1School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane, QLD, Australia
  • 2Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
  • 3Australian Bureau of Meteorology, Melbourne, VIC, Australia
  • 4Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT, USA
  • 5School of Earth, Atmosphere and Environment, Monash University, Melbourne, VIC, Australia
  • 6CSIRO Environment, Aspendale, VIC, Australia

Global climate models perform particularly poorly over the Southern Ocean, resulting in persistent cloud and radiation biases. This is in part driven by incomplete understanding of the aerosol formation and transformations over the Southern Ocean and their influence cloud formation and properties. Oxidation of volatile sulfur compounds, in particular dimethyl sulfide (DMS), and the subsequent secondary particle formation, is an important source of aerosols in the Southern Ocean atmosphere (and in marine environments in general). This presentation will focus on terminal oxidation products of volatile sulfur compounds, namely sulfuric acid (SA) and methanesulfonic acid (MSA), in both gas and particle phase observed during the 2024 Multidisciplinary Investigations of the Southern Ocean (MISO) voyage (Jan – March 2024) aboard the Australian Research Vessel Investigator and covering the western Pacific sector of the Southern Ocean (110o – 150o E). These species are investigated and will be presented in the context of air mass origin and synoptic meteorology.

A notable feature of the voyage were periods of elevated gaseous MSA south of ~62o S, coinciding with increased particulate sulfate and MSA, as well as enhanced cloud condensation nuclei (CCN) concentrations. These periods were found to be associated with Antarctic continental outflow and the air masses to have free tropospheric origin. By using E-AIM thermodynamic modelling we show that aerosol particles during MISO voyage were highly acidic (pH < -1) and that the elevated gaseous MSA is a result of evaporation from these highly acidic particles. Evaporation of MSA from highly acidic aerosols during Antarctic continental outflow has already been reported for the 2018 CAPRICORN-2 voyage which covered a very similar geographical region (Miljevic et al., 2025). The recent MISO voyage further highlights long range transport as an important pathway for biogenically dominated CCN and brings into focus MSA gas-particle partitioning as a relevant process in the marine sulfur cycle.

Reference:

Miljevic, B., Mallet, M. D., Osuagwu, C. G., Ristovski, Z. D., Humphries, R. S., Selleck, P., Taylor, S., & Keywood, M. D. (2025). Aerosol acidity controls methanesulfonic acid evaporation from aerosols during Antarctic katabatic outflow. Communications Earth & Environment, 6(1), 1057. https://doi.org/10.1038/s43247-025-03041-2

How to cite: Miljevic, B., Alroe, J., Mallet, M. D., Muniraj Saraswathy, A., Protat, A., Mace, G. G., Barber, K., Avaronthan Veettil, S., Alinejadtabrizi, T., Humphries, R. S., and Taylor, S.: Antarctic Continental Outflow as a Transport Pathway for Elevated Gaseous MSA and Biogenically Dominated Cloud Condensation Nuclei: Insights from the MISO Voyage, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6049, https://doi.org/10.5194/egusphere-egu26-6049, 2026.