Aerosol formation in the Antarctic sea-ice region

• Main Author: Humphries, Ruhi
• Format: Thesis
• Language: unknown
• Published: School of Chemistry 2015
• Subjects: Southern Ocean; aerosols; atmospheric particles; atmospheric chemistry; atmospheric science; Antarctica; Southern Hemisphere circulation; mercury chemistry; Antarctic; Breaker; The Antarctic; Antarc*; aurora australis; Sea ice
• Online Access: https://ro.uow.edu.au/theses/4536; https://ro.uow.edu.au/cgi/viewcontent.cgi?article=5545&context=theses

Particles in the atmosphere, or aerosols, are vital components of many chemical and physical processes including the Earth's radiative balance. The mechanisms of aerosol formation, along with their interactions with clouds and subsequent effect on the radiative balance, are among the largest uncertainties present in our understanding of the climate system. Recent modelling studies have shown that the greatest gains in reducing these uncertainties will be achieved through the study of pristine, natural aerosol processes. There are very few observations in the Antarctic and Southern Ocean regions. Those that have been made have been primarily limited to boundary layer airmasses at spatially sparse coastal and continental research stations, or to ship-based measurements in the Southern Ocean. The dynamic Antarctic sea ice region, when at its maximum spatial extent, covers more area than the continent itself, however aerosol measurements within this region have only been performed once before. This thesis describes results from atmospheric measurements made on-board Australia’s flagship ice-breaker, Aurora Australis, during a marine science voyage to the sea ice region off the East Antarctic coast during the spring of 2012. Measurements of aerosols and various trace gases were made continually throughout the voyage, resulting in significant advances in the scientific understanding of the region which this research has shown to be atmospherically distinct from adjacent areas. The collected aerosol dataset has two main features. Firstly, background aerosol concentrations were higher than any other previously recorded in the Antarctic and Southern Ocean region. Secondly, a single new particle formation event was observed during the 32 day aerosol record which could not be explained by known nucleation chemistry.