A Millennial Proxy Record of ENSO and Eastern Australian Rainfall from the Law Dome Ice Core, East Antarctica

• Published in: Journal of Climate
• Main Authors: Vance, TR, van Ommen, TD, Curran, MAJ, Plummer, CT, Moy, AD
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Meteorological Soc 2013
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; East Antarctica; West Antarctica; Pacific; Law Dome; Antarc*; Antarctica; Antarctica Journal; ice core
• Online Access: https://doi.org/10.1175/JCLI-D-12-00003.1; http://ecite.utas.edu.au/81621

ENSO causes climate extremes across and beyond the Pacific basin; however, evidence of ENSO at high southern latitudes is generally restricted to the South Pacific and West Antarctica. Here, the authors report a statistically significant link between ENSO and sea salt deposition during summer from the Law Dome (LD) ice core in East Antarctica. ENSO-related atmospheric anomalies from the central-western equatorial Pacific (CWEP) propagate to the South Pacific and the circumpolar high latitudes. These anomalies modulate high-latitude zonal winds, with El Nio (La Nia) conditions causing reduced (enhanced) zonal wind speeds and subsequent reduced (enhanced) summer sea salt deposition at LD. Over the last 1010 yr, the LD summer sea salt (LDSSS) record has exhibited two below-average (El Niolike) epochs, 10001260 ad and 19202009 ad, and a longer above-average (La Nialike) epoch from 1260 to 1860 ad. Spectral analysis shows the below-average epochs are associated with enhanced ENSO-like variability around 25 yr, while the above-average epoch is associated more with variability around 67 yr. The LDSSS record is also significantly correlated with annual rainfall in eastern mainland Australia. While the correlation displays decadal-scale variability similar to changes in the interdecadal Pacific oscillation (IPO), the LDSSS record suggests rainfall in the modern instrumental era (19102009 ad) is below the long-term average. In addition, recent rainfall declines in some regions of eastern and southeastern Australia appear to be mirrored by a downward trend in the LDSSS record, suggesting current rainfall regimes are unusual though not unknown over the last millennium.