10 Nov 2020

10 Nov 2020

Review status: a revised version of this preprint was accepted for the journal CP.

El Niño Southern Oscillation signal in a new East Antarctic ice core, Mount Brown South

Camilla K. Crockart1, Tessa R. Vance1, Alexander D. Fraser1, Nerilie J. Abram2, Alison S. Criscitiello3, Mark A. J. Curran4,1, Vincent Favier5, Ailie J. E. Gallant6, Helle A. Kjær7, Andrew R. Klekociuk4,1, Lenneke M. Jong4,1, Andrew D. Moy4,1, Christopher T. Plummer1, Paul T. Vallelonga7,a, Jonathon Wille5, and Lingwei Zhang8 Camilla K. Crockart et al.
  • 1Australian Antarctic Program Partnership, Institute for Marine & Antarctic Studies, University of Tasmania, Hobart 7004, Australia
  • 2Research School of Earth Sciences and ARC Centre of Excellence for Climate Extremes, Australian National University, Canberra ACT 2601, Australia
  • 3Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, T6G 2R3, Canada
  • 4Australian Antarctic Division, Channel Highway, Kingston 7050, Australia
  • 5Institut des Géosciences de l’Environnement, Université Grenoble-Alpes, Grenoble, France
  • 6School of Earth, Atmosphere and Environment, Monash University, Rainforest Walk, Clayton 3800, Victoria
  • 7Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, Denmark
  • 8Institute for Marine & Antarctic Studies, University of Tasmania, Hobart 7004, Australia
  • anow at: UWA Oceans Institute, University of Western Australia, Perth 6909, Australia

Abstract. Paleoclimate archives, such as high-resolution ice core records, provide a means to investigate long-term (multi-centennial) climate variability. Until recently, the Law Dome (Dome Summit South) ice core record remained one of few long-term high-resolution records in East Antarctica. A new ice core drilled in 2017/2018 at Mount Brown South, approximately 1000 km west of Law Dome, provides an additional high-resolution record that will likely span the last millennium in the Indian Ocean sector of East Antarctica. Here, we compare snowfall accumulation rates and sea salt concentrations in the upper portion (~21 m) of the Mount Brown South record, and an updated Law Dome record over the period 1975–2016. Annual sea salt concentrations from the Mount Brown South record preserves a stronger signal for the El Niño-Southern Oscillation (ENSO; in austral winter and spring, r = 0.521, p < 0.000, Niño 3.4) compared to the Law Dome record (November–February, r = −0.387, p = 0.018, Niño 3.4). The Mount Brown South and Law Dome ice cores record inverse signals for the ENSO, suggesting the occurrence of distinct moisture and aerosol intrusions. We suggest that ENSO-related sea surface temperature anomalies in the equatorial Pacific drive atmospheric teleconnections in the southern mid-latitudes. These anomalies are associated with a weakening (strengthening) of regional westerly winds to the north of Mount Brown South that corresponds to years of low (high) sea salt deposition at Mount Brown South during La Niña (El Niño) events. The Mount Brown South annual sea salt record when complete will offer a new proxy record for reconstructions of the ENSO over the recent millennium, along with improved understanding of regional atmospheric variability in the southern Indian Ocean in addition to that derived from Law Dome.

Camilla K. Crockart et al.

Status: final response (author comments only)
Status: final response (author comments only)
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Camilla K. Crockart et al.

Data sets

AAS_4414_MountBrownSouth_LawDome_icecores_seasalt_accumulation_2020 Camilla K. Crockart, Tessa R. Vance, Alexander D. Fraser, Nerilie J. Abram, Alison S. Criscitiello, Mark A. J. Curran, Vincent Favier, Ailie J. E. Gallant, Helle A. Kjær, Andrew R. Klekociuk, Lenneke M. Jong, Andrew D. Moy, Christopher T. Plummer, Paul T. Vallelonga, Jonathon Wille, and Lingwei Zhang

Camilla K. Crockart et al.


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Short summary
Preliminary analyses of the annual sea salt concentrations and snowfall accumulation in a new East Antarctic ice core, Mount Brown South. We compare this record with an updated Law Dome (Dome Summit South site) ice core record over the period 1975–2016. The Mount Brown South record preserves a stronger and inverse signal for the El Niño Southern Oscillation (in austral winter and spring) compared to the Law Dome record (in summer).