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SUBGLACIOR: revolutionising paleoclimatology with a new type of probe

Design, build and deploy a new type of in-situ ice-corer probe in the Antarctic in order to record, within a single season, the oldest available data on the earth’s climate sourced from natural ice that formed over a million years ago. These are the goals of the SUBGLACIOR project developed since 2011 and notably supported by the French National Research Agency under the "Blanc" funding programme.

SUBGLACIOR gathers the expertise of four French research laboratories: the Laboratory for Environmental Glaciology and Geophysics (LGGE, CNRS/Université Joseph Fourier), the Interdisciplinary Physics Laboratory (LIPhy, CNRS/Université Joseph Fourier), the technical division of the National Institute of the Sciences of the Universe of CNRS (DT-INSU) and the Laboratory for Climate and Environmental Sciences (LSCE, CNRS/CEA/UVSQ).

SUBGLACIOR is financed by the European Research Council (ERC), the French National Research Agency (ANR), the BNP Paribas Foundation, the “Investments for the Future” programme under the CLIMCOR Equipex project, and the Paul-Emile Victor French Polar Institute (IPEV). It is the main focus of the International Partnerships in Core Ice Sciences, an organisation which brings together scientists from 23 countries working on ice cores.

Throwing light on the last major climate system shift

The natural climate archives have shown that a radical change in climatic variability took place around a million years ago. The earth went from experiencing low intensity but frequent – every 40,000 years – periods of glaciation to longer and more pronounced periods of glaciation every 100,000 years. This change in the climate may be due to a major alteration in the concentration of CO2 in the earth’s atmosphere.

In order to verify this hypothesis and thus resolve one of the last great enigmas of climate history, glaciologists set out to retrieve samples of the oldest ice, which is located at the very bottom of the Antarctic mass, so as to analyse the air it contains. This reliable method enables scientists to understand the mechanisms, non-linear variations and retroactive effects of this mid-Pleistocene climate shift.
With the drilling technology available today, efforts to attain the research objectives carry considerable risks of scientific inaccuracy due to the difficult of identifying the right site for drilling – i.e. where the various layers of ice have not become mixed up. The task will take a number of years.

With their new approach, the SUBGLACIOR project team will be able to substantially reduce the risk of inaccuracy. The probe that is being developed will enable the scientists to explore the ice up to 3 kilometres deep in a single season in the field, i.e. 2 to 3 months, and collect precise real time data on the climate over the last 1.5 million years, concentrations of greenhouse gases and dust particles.

Development of the SUBGLACIOR probe

The probe’s measurement capability is based on innovative French laser technology which enables key parameters, such as water isotopes and the concentration of methane in the air imprisoned in the ice, to be measured in real time relative to the drilling process by means of an instrument embedded in the corer. Progress in laser spectroscopy in the near and mid infrared ranges – OFCEAS-patented technology – means that ultra-precise measurements can now be obtained from an instrument compact and robust enough to be deployed in extreme conditions. As part of the SUBGLACIOR project, around twenty scientists and engineers on the team succeeded in miniaturising the laser instrument so that it could be inserted into a tube less than 5 centimetres in diameter. The data it will gather will be transmitted continuously to the surface via electronics embedded in the probe, and a specially designed cable 3,500 metres in length.

The SUBGLACIOR team is now developing an envelope which will allow the probe to drill down into the ice cap from the surface and produce continuous samples analysed by the laser spectrometer. 

The laser instrument was tested for the first time last summer, in an environment far from the polar ice. It was deployed to analyse gases dissolved in the Mediterranean Sea, using a specially-designed interface built at the LGGE. In fact the initial results look very promising for use in many areas of oceanography, a field far removed from research into ancient climate history. This deployment at depths of up to 600 metres off the coast of Nice allowed scientists to obtain for the first time a continuous profile of methane concentrations dissolved in the Mediterranean Sea, showing variations at the scale of just several dozen metres. It now remains to be established whether these variations are of biological origin or linked to sea currents.

Next steps

Following a development phase lasting four years, the mechanical part of the probe was tested for the first time in situ during the winters of 2013-14 and 2014-15 at the Franco-Italian Concordia base station in Antarctica. A fully watertight tube system was for the first time installed down through the 120 metres of snow and névé covering the glacier. The tubing is necessary as the circulation of drilling fluid continually delivers to the surface ice shavings produced during drilling. Having tested this circulating fluid mixed with ice shavings, the scientists were able to show conclusively that the system is indeed watertight and that the core samples are not being contaminated.

The next expedition will take place during the 2015-16 winter. Logistics experts from IPEV will transport the heavy equipment – drilling fluid, winch, winch cable, drilling fluid feed hose, etc. – to the Antarctic coast so that the probe can be set up at the Concordia base and tested in an on-site trial scheduled to take place the following year.

In parallel, research into gases dissolved in the oceans – an initially unforeseen application of these technological advances – is continuing. An important area for the team to focus on is the study of the release of gases from methane hydrates in the sea floor in the Arctic region as a result of global warming. Oceanographic researchers are very excited about the performance of the prototype instrument. The SUBGLACIOR team is now looking at the potential for creating a start-up company to arrange manufacture and commercialisation this new French knowhow.

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Project funding and organisation

The total budget for constructing the probe is around €3.2 million.

BNP Paribas Foundation sponsorship totalling €100,000 enabled the four research centres involved to start work on designing the probe.

The construction and on-site deployment of the probe in the Antarctic is being financed by the European Research Council through the ICE&LASERS project, the French National Research Agency under its ‘Blanc’ (Blue-sky) programme (project coordinated by Olivier Alemany, LGGE Lab, for an amount of 320,000 €), CLIMCOR EquipEX (Equipment of Excellence) from the Investments for the Future programme and the Mamont Foundation, which recently joined the consortium.

The Paul-Emile Victor French Polar Institute (IPEV) is handling the logistics for the Antarctic missions to deploy the probe.

 

 

26.03.15