Proxy Records of El Niño-Southern Oscillation and East Australian Rainfall from the Law Dome Ice Core, East Antarctica

The El Niño-Southern Oscillation (ENSO) is a major climate mode with variability on a variety of timescales important to society. Climatic extremes such as bushfires, flooding and drought across the tropical Pacific region result from switches in state of the ENSO system, however remote effects of ENSO influence climate in areas outside the tropical Pacific Basin. Evidence that ENSO affects climate at high southern latitudes and Antarctica are comparatively scarce, however this is at least partially due to the paucity of instrumental records from Antarctica and the Southern Ocean. Here we report a link between ENSO and summer sea salt concentrations in a high resolution coastal ice core from Law Dome, East Antarctica. The relationship occurs via an atmospheric teleconnection between ENSO-forced sea surface temperature (SST) and sea level pressure (SLP) anomalies in the Central-Western Equatorial Pacific (CWEP) and atmospheric anomalies in the South Pacific sector of the Southern Ocean during austral winter. During the winter/spring preceding El Niño (La Niña) conditions, an atmospheric Rossby wave train weakens (strengthens) a quasi-stationary low pressure system in the Amundsen and Bellingshausen Seas. As summer approaches this develops into a polar ridge-like (trough-like) anomaly stretching across much of the Antarctic continent and coastal regions that manifests as a weakening (strengthening) of summertime polar westerlies and results in decreased (increased) sea salt concentrations in summer precipitation at LD. The Law Dome ice core record has continuous subseasonal resolution to 1 kya and spectral analysis of this record shows broadly persistent ENSO band features (4-7 years) throughout the last millennium.