A synoptic bridge linking sea salt aerosol concentrations in East Antarctic snowfall to Australian rainfall

• Main Authors: Udy, Danielle G., Vance, Tessa R., Kiem, Anthony S., Holbrook, Neil J.
• Other Authors: The University of Newcastle. College of Engineering, Science & Environment, School of Environmental and Life Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2022
• Subjects: aerosol; sea salt concentrations; East Antarctica; southern ocean wind; Eastern Australia; rainfall; Antarctic; Law Dome; Southern Ocean; Antarc*; Antarctica; ice core
• Online Access: http://hdl.handle.net/1959.13/1446972

Previous research has shown that aerosol sea salt concentrations (Southern Ocean wind proxy) preserved in the Law Dome ice core (East Antarctica) correlate significantly with subtropical eastern Australian rainfall. However, physical mechanisms underpinning this connection have not been established. Here we use synoptic typing to show that an atmospheric bridge links East Antarctica to subtropical eastern Australia. Increased ice core sea salt concentrations and wetter conditions in eastern Australia are associated with a regional, asymmetric contraction of the mid-latitude westerlies. Decreased ice core sea salt concentrations and drier eastern Australia conditions are associated with an equatorward shift in the mid-latitude westerlies, suggesting greater broad-scale control of eastern Australia climate by southern hemisphere variability than previously assumed. This relationship explains double the rainfall variance compared to El Niño-Southern Oscillation during late spring-summer, highlighting the importance of the Law Dome ice core record as a 2000-year proxy of eastern Australia rainfall variability.