Aerosol particle measurements on the Southern Ocean during the Southern Ocean Clouds (SOC) campaign in November and December 2024

We deployed an Aerosol Mass Spectrometer (AMS) on the British Antarctic Survey Research Vessel Sir David Attenborough (SDA) during November and December 2024 as part of the Southern Ocean Clouds (SOC) campaign. The AMS measures sub 1 micron aerosol particle chemical composition and size distributions, using thermal vaporization and electron impact ionization, followed by time-of-flight mass spectrometry.

The cruise track covered a broad area (50 S to 67 S and 70 W to 25 W) and encountered a wide variety of atmospheric environments, including seasonal sea ice zones, open ocean, and areas near islands with penguin colonies and volcanoes. Different ratios of organics, sulphate and methane sulphonic acid (MSA) were observed for different sympagic and pelagic air masses and associated with distinct aerosol size distributions. We also observed distinct plumes of NH4Cl particles from a volcano and we saw aqueous processing of aerosol particles during a multi-day fog event. As is typical of ship campaigns, the AMS organics showed that we were sampling ship emissions, both from the engines and from the kitchen, at least half of the time.