Climate change studies & ice core research

ice core research

The atmospheric tritium history is preserved in ice sheets in full detail, allowing for accurate dating of ice cores back hundreds of years - a vital element for global climate change studies.

Ice sheets play a fundamental role as archives for global climate change. They contain a variety of proxies for climate forcing, such as the greenhouse gases CO2 and CH, dust, aerosols and solar irradiance, as well as corresponding climate responses such as precipitation rate, temperature and wind strength. Accurate dating of ice cores is crucial to make full use of this information.

Tritium and 32-Silicon stored in the ice provide a precise natural clock for this purpose. 32Si, with a half-life of 140 years, is ideally suited to provide time information in the range 50-1000 years. Tritium, with a half life of 12.3 years, is ideally suited to provide time information in the range <80 years.

Dating of surface ice layers from glaciers in New Zealand’s Southern Alps suggest a total ice record of several hundred years. ( Dating of Southern Alps glacier ice.pdf (1.04 MB) ). While Franz Joseph and Fox glaciers have a records spanning only 40 and 50 years respectively, the surface age profile of the Tasman glacier spans 90 years, with several hundred meters of ice inaccessible to the surface yet to be analysed.

References

  • Morgenstern, U. 2004 Tritium dating of water and ice.New Zealand science review, 61(2): 42-44
  • Morgenstern, U.; Mayewski, P.A.; Bertler, N.; Ditchburn, R.G. 2004 Ice core research in the New Zealand Southern Alps. Geophysical research abstracts, 6: [http://www.asiaoceania.org/]
  • Morgenstern, U.; Mayewski, P.A.; Bertler, N.; Ditchburn, R.G. 2004 Ice core research in the New Zealand Southern Alps.p. 27 In: Alloway, B.V. (convenor) 2004 NZ-INTIMATE Meeting, GNS Rafter Laboratory, Wellington, 23-24 August 2004. Lower Hutt: Institute of Geological & Nuclear Sciences Limited. Institute of Geological & Nuclear Sciences science report 2004/22
  • Bertler, N.; Naish, T.R.; Morgenstern, U. 2004 Ice cores : the archive of rapid climate change.p. 16 In: Alloway, B.V. (convenor) 2004 NZ-INTIMATE Meeting, GNS Rafter Laboratory, Wellington, 23-24 August 2004. Lower Hutt: Institute of Geological & Nuclear Sciences Limited. Institute of Geological & Nuclear Sciences science report 2004/22
  • Patterson, N.G.; Bertler, N.A.N.; Naish, T.R.; Morgenstern, U. 2005 ENSO variability in the deuterium-excess record of a coastal Antarctic ice core from the McMurdo Dry Valleys, Victoria Land. Annals of glaciology, 41: 140-146