Ice Core Research

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Background on Ice Core Research Current Research Projects National Collaborators & Laboratory Facilities International Collaborations Who is working on this?

Background on Ice Core Research

New Zealand’s future economic and social development, environmental sustainability, and infrastructural planning relies critically upon the accurate assessment of the impact of “global warming” in our sector of the planet. Future climate change is a result of both natural variability and anthropogenic influence. A major problem is that natural variability can involve large, abrupt switches in Earth’s climate, and the cumulative effects of anthropogenic influences remain highly uncertain.

Ice core records provide an annual-scale, “instrumental-quality” baseline of atmospheric temperature and circulation changes back many thousands of years. Their analysis has allowed human-induced warming on a global scale to be extracted from the background climate state and the fundamental non-linear behaviour of the climate system at inter-decadal to century-scale (e.g. ENSO) to be evaluated.

The scientific goal of the VUW/GNS ice core programme is to improve our understanding of the major Southern Hemisphere climate drivers causing high frequency climate variability. These are in particular the El Niño Southern Oscillation, the Antarctic Oscillation, and the Antarctic Circumpolar Wave, as well as feedback mechanisms causing abrupt climate change, such as changes in sea ice cover or ice shelf instability. Many of these climate drivers operate on rapid time scales (sub-decadal) and potentially respond to longer term forcings (centennial to millennial). It is therefore important to obtain high resolution (sub-annual) records that can reliably capture the high frequency variability of these drivers from sites that are particularly sensitive to their influence, while at the same time providing a long enough record to investigate superimposed longer-term trends.

We have identified key locations from low elevation, coastal sites. These sites are particularly climate sensitive, as they capture tropospheric climate variability and in general have a higher snow accumulation rate than sites from the Antarctic interior. This makes these sites ideal when investigating abrupt and rapid climate change.

Current Research Projects

We are involved in several collaborative projects in this field:

• ANZICE
• ANDRILL - Ice Cores Correlation
• GCT
• NZ ITASE
• Latitudinal Gradient Project (LGP)
• Antarctica in the Global Climate System (AGCS)
• Holocene Greenhouse Gas Concentration and Isotopic Signatures
• Ross Ice Shelf Stability
• The Antarctic – New Zealand Connection
• Longer-Term Mass Balance Objective

ANZICE

ANZICE (Antarctica-New Zealand Interglacial Climate Extremes) seeks tounderstandthe likely response of the New Zealand - Antarctic region to a warmer world. To help achieve this aim, the project will use new andexistingrecords from ice cores to determine how Antarctica’s climate and ocean behaved during past warm phases such as occurred around 7,000-9,000 years ago (Holocene Climatic Optimum) and 125,000 yearsago (Last Interglacial Period or Stage 5e).

ANDRILL – Ice Core Correlation

Two of our ice core locations (Mt. Erebus and Evans Piedmont) are in the immediate vicinity of ANDRILL coring locations (Windless Bight and Granite Harbour). The ice core records will provide a terrestrial high-resolution climate dataset for the younger part of marine record recovered through ANDRILL. This will provide the unique opportunity to compare contemporary on- and off-shore records.

For more information see http://www.andrill.org

GCT
Global Change Through Time is a FRST-funded GNS Science programme and examines past analogues for future global change at a wide range of geographic and temporal scales: from variation in local catchments over thousands of years to the evolution of Antarctic-sourced ocean currents over tens of millions of year. This range of scale reflects the wide spectra over which climatic and oceanographic systems evolve. Data are drawn from onshore New Zealand, the Southwest Pacific and Southern Ocean, and Antarctica. Current research aims to improve understanding of the effects of anthropogenic, greenhouse gas-induced, global warming.

For more information see http://www.gns.cri.nz/research/sub_dir/gct.html

NZ ITASE

ITASE (International Trans Antarctic Scientific Expedition) is a SCAR (Scientific Committee of Antarctic Research) approved programme and has as its primary aim “the collection and interpretation of a continent-wide array of environmental parameters, assembled through the coordinated efforts of scientists from 20 nations” (Mayewski 2006, PAGES, vol.14, no.1,26-28).

The NZ contribution to ITASE concentrates on coastal sites, predominantly from low elevation, local ice domes.

Mid-latitude Southern Hemisphere climate is particularly sensitive to changes in the position and strength of the circumpolar westerlies, which are dependent on the relative input of Antarctic air masses. Antarctic atmospheric circulation on inter-annual to decadal timescales is dominated by El Niño Southern Oscillation (ENSO), Southern Annular Mode or Antarctic Oscillation (SAM) and Antarctic Circumpolar Wave (ACW), but their hierarchy of importance is controversial. While some researchers suggest SAM as the driving forcing of the regions climate, others argue that the ACW is dominating the continent’s climatic regime. In contrast, we demonstrated from coastal ice cores in McMurdo Sound that ENSO governs temperature variability in the Ross Sea region. Meteorological observations are too short and sparse to resolve this uncertainty. In order to quantify the relative importance of each of these oscillations on the climate of the mid to high latitudes and their tele-connections, high-resolution climate proxies are required. We study intermediate length (<500m) ice cores from the Ross Sea region. The sites have been chosen on their basis of their sensitivity to different climate drivers and the synthesis of all records will help to examine their individual influence and variability.

Ground penetrating radar is used to map bedrock topography, ice thickness, and internal flow structures. Then ~4m deep snow pits are sampled with high resolution (1cm) and intermediate depth ice cores are recovered.

For more information see http://www.ume.maine.edu/itase/

Latitudinal Gradient Project (LGP)

LGP is an international effort between NZ, USA, and Italy. We contribute to LGP by providing a history of temperature, humidity, sea ice cover, precipitation source, atmospheric circulation, and ocean productivity along the Victoria Coast for the last 1000 to 10,000 years depending on the site. This will help to determine whether the current ecological system found has evolved under prevailing climate, or how much time the ecological system had to adjust to potential climate change in the recent past.

For more information see http://www.lgp.aq/

Antarctica in the Global Climate System (AGCS)

AGCS is a multinational, SCAR approved programme investigating atmospheric and oceanic linkages between Antarctica and the rest of the Earth system for the last 10,000 years and 100 years into the future. The programme integrates existing and new ice core records, satellite data, fully coupled climate models and meteorological and oceanic data.

The scientific aims of AGCS are grouped into the four themes. The New Zealand ice core programme aims to contribute to themes 1, 2, and 4:

• Theme 1 - Decadal time scale variability in the Antarctic climate system
• Theme 2 - Global and regional climate signals in ice cores
• Theme 4 - The export of Antarctic climate signals

For more information see
http://www.scar.org/researchgroups/physicalscience/agcs/

Holocene Greenhouse Gas Concentration and Isotopic Signatures

In collaboration with Dr. Dominic Ferretti and Dr. Katja Riedel at NIWA we analyse a new ice core recovered from a high snow accumulation zone on Mt Erebus, Antarctica, with rapid air bubble closure, which affords an opportunity to construct a GHG record of similar or potentially even higher resolution than the Australian Law Dome record for the last millennium. In addition, we will analyse the carbon isotopic composition of the GHG to fingerprint the sources of the carbon to better understand the role of the ocean, atmosphere, and the terrestrial biosphere sources and sinks. This will improve understanding of pathways and processes that determine variations in atmospheric GHGs in the recent past, and help us gauge their influence in the future.

Ross Ice Shelf Stability

The timing and velocity of the Ross Ice Shelf retreat some 9 to 5ka years ago is still discussed controversially. Coastal ice core records are very sensitive to the change from an ice shelf environment to seasonally open water, which manifests itself in a shift in the chemical signature of snow and aerosol precipitation. By dating the occurrence of the characteristic chemistry shift in the proposed ice cores locations, average retreat velocity can be calculated and its dependency on air temperature tested. Our sites are located along the retreat line at the Victoria Land Coast and Marie Byrd Land. Together with additional cores from our international collaboration partners, we aim to reconstruct the velocity of the ice shelf retreat as well as contemporary environmental conditions.

The Antarctic – New Zealand Connection

New Zealand’s future economic and social development, environmental sustainability, and infrastructural planning relies critically upon the accurate assessment of the impact of “global warming” in our sector of the planet. A joint programme between GNS Science and the University of Maine led by Dr Uwe Morgenstern is investigating ice core records from New Zealand (Tasman Glacier and Mt. Ruapehu ice field). The comparison between our Antarctic ice core records and Dr. Morgenstern’s NZ ice core records will provide much needed data for the development of realistic regional climate models to predict NZ climate in the 21st Century.

For more info on Tasman ice core project please see:
http://www.gns.cri.nz/research/gct/tasman.html

Longer-Term Mass Balance Objective

During the 1999/2000 season mass balance measurement devices (submerge velocity method) have been deployed at Victoria Lower Glacier and at Evans Piedmont Glacier during 2004/05. The measurements at Victoria Lower Glacier show that the glacier has a slightly negative mass balance, losing around 12cm thickness per year. A continuation of the measurements will allow monitoring changes in the ablation intensity of the McMurdo Sound Region.

National Collaborators and Laboratory Facilities

We have collaborations and links in New Zealand with:

• Victoria University of Wellington
• GNS Science
• NIWA (National Institute of Water & Atmosphere Ltd)
• Antarctica New Zealand
• Scan Tec Ltd
• Webster Drilling & Exploration Ltd

Victoria University of Wellington

Since 1999 we have developed the first NZ ice core programme and a new branch of ice core climatology using ice core records from low elevation coastal regions. We are using a continuous melter system developed by the Climate Change Institute, University of Maine. This system allows us to sample the core with sub-centimetre resolution under ultra-clean conditions. Furthermore, we are currently working towards a NZ owned 500 m ice core drilling system. In addition, the newly constructed ICP-MS laboratory at the School of Geography, Environment and Earth Sciences provides the opportunity to measure concentration and isotopic signatures of trace elements, such as lead, mercury, phosphate, iron, aluminium to name but a few.

Nancy Bertler (Programme Leader ice cores)
Alex Pyne (Projects Manager)
Peter Barrett (sedimentology, past and future climate)
Tim Naish (Antarctic geology, global climate systems)
Lionel Carter (marine geology)
Gavin Dunbar (sedimentology)
Joel Baker (geochemistry and Igneous petrology)
Tamsin Falconer (Centre Manager)
Rachael Rhodes (PhD candidate)
Heather Purdie (PhD candidate)
Julia Bull (MSc candidate)

GNS Science

GNS Science has a state of the art ice core facility including a storage freezer at -30°C with a capacity of 2000 m of ice, a processing freezer at -18°C, and a warm laboratory for ultra clean sample processing. Furthermore, GNS has capacities for water isotopes (δD and δ¹⁸O), radioactive isotopes (³²Si, ³H, ¹⁰Be, ¹⁴C), and dexa measurements for high resolution density measurements.

Nancy Bertler (Programme Leader ice cores)
Kate Sinclair (ice core climatology)
Tim Naish (sedimentology)
James Crampton (paleontology)
Valerie Claymore (Team Leader Stable Isotope Laboratory)
Julian Thomson (Ice Core Technician, educational outreach)
Kevin Faure (Environmental Isotopes Section Manager)
Chris Kroger (Dexa xray)
Frank Bruhn (General Manager, National Isotope Centre)
Uwe Morgenstern (isotope hydrology)
Albert Zondervan (Team Leader Accelerator Operations)

For more information see http://www.gns.cri.nz/nic/ice/index.html

NIWA

NIWA has a long history of measuring concentration and isotopic ratios of greenhouse gases from the atmosphere and ice cores, in particular CO₂, CH₄, NO_x, δ¹⁸O. Furthermore, NIWA is currently developing an extraction device in collaboration Dr. David Etheridge to allow gas extraction in the NZ ice core facility.

Katja Riedel (greenhouse gases-concentration & isotope)
Peter Franz (greenhouse gases-concentration & isotope)
Hinrich Schaefer (greenhouse gases-concentration & isotope)

For more information see http://www.niwa.co.nz

Antarctica New Zealand

Antarctica New Zealand is charged by the Ministry for Foreign Affairs with the development, management, and administration of NZ’s activities in Antarctica and the Southern Ocean and maintains Scott Base, the NZ base in Antarctica. We are grateful for the support we have received from Antarctica New Zealand and Scott Base staff for our NZ ITASE programme since 1999. In six field seasons we recovered six shallow and intermediate depth ice cores, sampled 13 high resolution snow pits, and undertook three extensive ground penetrating radar surveys. We have currently one automatic weather station and two mass balance measurement devices (submerge velocity method) deployed.

For more information see http://www.antarcticanz.govt.nz/

Scan Tec Ltd

All our ground penetrating radar surveys were conducted by Matt Watson, Director of Scan Tec Ltd. Ground penetrating radar (GPR) measurements provide an image of the internal layering of a glacier and the topography of the ice-rock interface beneath. We applied low and high frequency radar pulses (35 MHz, 200MHz, and 400MHz) to map the bedrock interface and internal flow structures in the glacier. Those features are identified through reflectors that result from changes in physical and chemical properties, such as dust layers or aerosol and density variations and are thought to represent isochrones. The choice of antenna frequency involves a trade-off between penetration depth and mapping resolution. The control units were mounted on a Nansen Slege, pulling transmitter and transceiver antennae. The sledge also carried high precision GPS antenna, which is tied to the temporary GPS base station deployed at the Evans Piedmont Glacier camp.

Traverses totaling approximately 60 km have been surveyed with GPR. The measurements show glacier thickness, bedrock topography, and excellent isochrone reflections. This information is used to investigate geographical and chronological accumulation changes. Further post-processing will enhance the reflectors and will correct for surface topography.

For more information see http://www.scantec.co.nz/

Webster Drilling & Exploration Ltd

Webster Drilling is a drilling company with specialised Antarctic drilling experience such as ANDRILL and led the drilling of our intermediate depth (~200 m) cores together with Alex Pyne (VUW). We are particularly indebted to Tony Kingan.

For more information see http://www.websterdrilling.com

International Collaborations

We have collaborations and links internationally with:

• Climate Change Institute, University of Maine, USA
• Alfred Wegener Institute (AWI), Germany
• Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen
• Department of Microbiology, University of Hawaii-Manoa, USA
• Quaternary Research Center, University of Washington, USA
• Ice Coring and Drilling Service (ICDS) at University of Wisconsin, USA
• ITASE (International Trans Antarctic Scientific Expedition)
• AGCS (Antarctica in the Global Climate System)
• IPICS (International Partnerships in Ice Core Sciences)

Climate Change Institute, University of Maine, USA

We have a longstanding and close collaboration with the ice core team of CCI. In addition many thousands of our samples have been measured for their chemical and isotopic values in the facilities of the CCI. For the fruitful scientific exchange and laboratory support we are particularly indebted to Prof. Paul Mayewski, Ms. Sharon Sneed, Mr. Andrei Kurbatov, Mr. Mike Handley, Mr. Eric Meyerson, Mr. Erich Osterberg, Ms. Susan Kaspari, Mr. Dan Dixon, Dr. Karl Kreutz, Mr. Cap Introne, Ms. Tiffany Wilson, and Ms. Ann Zielinski.

For more information see http://www.climatechange.umaine.edu/

Alfred Wegener Institute (AWI), Germany

We are particularly indebted to Prof. Heinz Miller, Dr. Sepp Kipfstuhl, and Dr. Hans Oerter from AWI for their support and input to our projects at the Evans Piedmont Glacier and Mt Erebus Saddle. Furthermore, AWI kindly provided their intermediate depth drilling system and δ¹⁸O measurements.

For more information see http://www.awi.de/en/home/

Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen

For more information see http://www.iceandclimate.nbi.ku.dk/

Department of Microbiology, University of Hawaii-Manoa, USA

For more information see http://www.hawaii.edu/microbiology/

Quaternary Research Center, University of Washington, USA

For more information see http://www.ess.washington.edu/

Ice Coring and Drilling Service (ICDS) at University of Wisconsin, U.S.A.

ICDS supports research in both polar regions and has kindly provided their intermediate drilling equipment for our drilling operation at Victoria Lower Glacier. We are particularly grateful to Dr. Charlie Bentley and Mr. Bruce Koçi for their support and advice.

For more information see http://www.ssec.wisc.edu/icds/

ITASE (International Trans Antarctic Scientific Expedition)

Through our participation with ITASE we have entered a formal collaboration with 19 other nations.

For more information see http://www.ume.maine.edu/itase/

AGCS (Antarctica in the Global Climate System)

Through our participation with AGCS we have entered a formal collaboration with six other nations.

For further information see
http://www.scar.org/researchgroups/physicalscience/agcs/

IPICS (International Partnership in Ice Core Sciences)

IPICS is a planning group comprising scientists, drillers, and engineers from 18 nations. Its primary aim is to facilitate, plan, and organise the international, collaborative effort of the ice core science community to address important science questions and technological developments for next few decades.

For further information see
http://www.pages-igbp.org/science/initiatives/ipics/

Who is working on this?

For all enquiries on Ice Core Research, please contact Nancy Bertler.