CAPE-K-AEROSOLS

CAPE-k Summertime Single-Particle and INP Campaign

1 February 2025 - 30 April 2025

Lead Scientist: Kerri Pratt

Observatory: AMF (ARM Mobile Facility 2) - KCG

Aerosol-cloud interactions define the highly uncertain energy budget over the Southern Ocean. The unique oceanic microbial community and biogeochemical processes of this pristine region define the atmospheric aerosol population that nucleates clouds, influencing cloud properties and precipitation. There is a dearth of Southern Ocean observations, limiting understanding of the large biases in climate model simulations compared to satellite observations and pointing to limited aerosol process understanding. 

The overarching objective of this ARM field campaign is to improve understanding and predictability of Southern Ocean aerosol concentrations, chemical composition, and sources, and their relationship to cloud condensation nuclei (CCN) and ice nucleating particles (INPs). Intensive atmospheric aerosol sampling of Southern Ocean air masses will be conducted at Kennaook/Cape Grim, Tasmania, Australia from mid-Feb.–mid-Apr. 2025 during the ARM Cloud and Precipitation Experiment at Kennaook (CAPE-k). The collected atmospheric particles will be analyzed by single-particle (0.03-10 µm) chemical composition measurements (including electron microscopy, Raman, and photothermal infrared methods). These new data will be combined with additional ARM and Australian-led measurements to enable identification of aerosol sources in Southern Ocean air masses that influence Southern Ocean clouds through their action as CCN and/or INPs. This ARM field campaign will contribute to the Atmospheric System Research Aerosol Processes and High-Latitude Processes working groups, as well as to the international PICCAASO (Partnerships for Investigating Clouds and the biogeoChemistry of the Atmosphere in Antarctica and the Southern Ocean) initiative.