T. D. van Ommen

Australian Antarctic Division

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Co-Authors

Mark A. J. Curran

Antarctic Climate and Ecosystems Cooperative Research Centre

Jason L. Roberts

University of California, San Diego

Andrew D. Moy

University of Tasmania

Vin Morgan

Australian Antarctic Division

Tessa R. Vance

Antarctic Climate and Ecosystems Cooperative Research Centre

D. A. Young

The University of Texas at Austin

Jamin S. Greenbaum

University of California, San Diego

Martín J. Siegert

University of Exeter

D. D. Blankenship

The University of Texas at Austin

Paul A. Mayewski

University of Maine

Cooperative Institutions

Centre National de la Recherche Scientifique

University of Tasmania

Australian Antarctic Division

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

Commonwealth Scientific and Industrial Research Organisation

British Antarctic Survey

University of Bern

Antarctic Climate and Ecosystems Cooperative Research Centre

University of Copenhagen

Laboratoire des Sciences du Climat et de l'Environnement

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Research Field

Ice Core Evidence for Antarctic Sea Ice Decline Since the 1950s

Science (2003)

Mark A. J. Curran T. D. van Ommen Vin Morgan Katrina L. Phillips Anne S. Palmer

The instrumental record of Antarctic sea ice in recent decades does not reveal a clear signature of warming despite observational evidence from coastal Antarctica. Here we report a significant correlation (P < 0.002) between methanesulphonic acid (MSA) concentrations from a Law Dome ice core and 22 years of satellite-derived sea ice extent (SIE) for the 80 degrees E to 140 degrees E sector. Applying this instrumental calibration to longer term MSA data (1841 to 1995 A.D.) suggests that there has been a 20% decline in SIE since about 1950. The decline is not uniform, showing large cyclical variations, with periods of about 11 years, that confuse trend detection over the relatively short satellite era.

Ice core

10.1126/science.1087888

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Citations (368)

Insignificant Change in Antarctic Snowfall Since the International Geophysical Year

Science (2006)

Andrew J. Monaghan David H. Bromwich Ryan L. Fogt Sheng‐Hung Wang Paul A. Mayewski

Antarctic snowfall exhibits substantial variability over a range of time scales, with consequent impacts on global sea level and the mass balance of the ice sheets. To assess how snowfall has affected the thickness of the ice sheets in Antarctica and to provide an extended perspective, we derived a 50-year time series of snowfall accumulation over the continent by combining model simulations and observations primarily from ice cores. There has been no statistically significant change in snowfall since the 1950s, indicating that Antarctic precipitation is not mitigating global sea level rise as expected, despite recent winter warming of the overlying atmosphere.

Antarctic ice sheet

Ice core

10.1126/science.1128243

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Citations (250)

Extending and understanding the South West Western Australian rainfall record using a snowfall reconstruction from Law Dome, East Antarctica

Climate of the past (2021)

Yaowen Zheng Lenneke M. Jong Steven J. Phipps Jason L. Roberts Andrew D. Moy

Abstract. South West Western Australia (SWWA) has experienced a prolonged reduction in rainfall in recent decades, with associated reductions in regional water supply and residential and agricultural impacts. The cause of the reduction has been widely considered but remains unclear. The relatively short length of the instrumental record limits long-term investigation. A previous proxy-based study used a statistically negative correlation between SWWA rainfall and snowfall from the Dome Summit South (DSS) ice core drilling site, Law Dome, East Antarctica, and concluded that the anomaly of recent decades is unprecedented over the ∼ 750-year period of the study (1250–2004 CE). Here, we extend the snow accumulation record to cover the period from 22 BCE to 2015 CE and derive a rainfall reconstruction over this extended period. This extended record confirms that the recent anomaly is unique in the period since 1250 CE and unusual over the full ∼ 2000-year period, with just two other earlier droughts of similar duration and intensity. The reconstruction shows that SWWA rainfall started to decrease around 1971 CE. Ensembles of climate model simulations are used to investigate the potential roles of natural variability and external climate drivers in explaining changes in SWWA rainfall. We find that anthropogenic greenhouse gases are likely to have contributed towards the SWWA rainfall drying trend after 1971 CE. However, natural variability may also have played a role in determining the timing and magnitude of the reduction in rainfall.

Ice core

Proxy (statistics)

Summit

Anomaly (physics)

10.5194/cp-17-1973-2021

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Citations (16)

A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes

Nature (2011)

D. A. Young Andrew Wright Jason L. Roberts Roland Warner N. W. Young

Antarctic ice sheet

Fjord

Ice divide

10.1038/nature10114

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Citations (196)

Proxy records of El Niño-Southern Oscillation and East Australian rainfall from the Law Dome ice core, East Antarctica

Tessa R. Vance T. D. van Ommen M. A. J. Curran Christopher Plummer AD Moy

The El Nino-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 Nino (La Nina) 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.

Ice core

Teleconnection

Westerlies

Source

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Citations (0)

Temporal and spatial patterns of snow accumulation on Law Dome

S Woon VI Morgan T. D. van Ommen

Dome (geology)

Source

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Citations (0)

A high resolution SOI proxy from the Law Dome ice core

Tessa R. Vance T. D. van Ommen M. A. J. Curran Christopher Plummer

Proxy (statistics)

Dome (geology)

Ice core

Source

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Citations (0)

Persistent Low Frequency Blocking Anomalies In The Southern Hemisphere Extratropical Atmospheric Longwave Pattern During The Medieval Climate Anomaly

AGU Fall Meeting Abstracts (2011)

Ian Goodwin Stuart Browning Andrew Lorrey Paul A. Mayewski N. N. Bertler

Extratropical cyclone

Longwave

Anomaly (physics)

Outgoing longwave radiation

Blocking (statistics)

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Citations (0)

Where to find 1.5 million yr old ice for the IPICS "Oldest Ice" ice core

Hubertus Fischer Jeffrey P. Severinghaus Edward J. Brook E. W. Wolff M. R. Albert

Abstract. The recovery of a 1.5 Myr long ice core from Antarctica represents a keystone to our understanding of Quaternary climate, the progression of glaciation over this time period and the role of greenhouse gas cycles in this progression. Here we show that such old ice is most likely to exist in the plateau area of the East Antarctic Ice Sheet (EAIS) without stratigraphic disturbance and should be able to be recovered after careful pre-site selection studies. Based on a simple ice and heat flow model and glaciological observations, we conclude that positions in the vicinity of major domes and saddle positions on the East Antarctic Plateau will most likely have such old ice in store and represent the best study areas for dedicated reconnaissance studies in the near future. In contrast to previous ice core drill site selections, we strongly argue for significantly reduced ice thickness to avoid bottom melting, while at the same time maximizing the resolution and the distance of such old ice to the bedrock. For example for the geothermal heat flux and accumulation conditions at Dome C, an ice thickness lower than 2500 m would be required to find 1.5 Myr old ice. However, the final choice is strongly dependent on the local geothermal heat flux, which is largely unknown for the EAIS and has to be determined beforehand. In addition, the detailed bedrock topography and ice flow history for candidates of an Oldest Ice ice coring site has to be reconstructed. Finally, we argue strongly for rapid access drilling before any full deep ice coring activity commences to bring datable samples to the surface and to allow an age check of the oldest ice.

Ice divide

Ice-albedo feedback

Iceberg

Ice core

Ice-sheet model

Lead (geology)

Antarctic ice sheet

Dome (geology)

10.5194/cpd-9-2771-2013

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Citations (6)

Late Pleistocene and early Holocene change in the Weddell Sea: a new climate record from the Patriot Hills, Ellsworth Mountains, West Antarctica