Last Millenium Climate Variability At Law Dome, Coastal Eastern Antarctica
Abstract
Water stable isotopes (oxygen 18 and deuterium) have been measured along two ice cores from Law Dome, coastal eastern Antarctica. Theoretical studies have shown that the second-order isotopic parameter, the deuterium excess (d=dD-8d18O), is an indi- cator of climatic conditions at the oceanic moisture source (actually dominated by the southern Indian ocean at Law Dome) reflecting at least partly changes in sea-surface- temperature. A first deuterium excess record has been obtained on DE08-2 ice core, covering the 1930-1990 period with a monthly resolution. The comparison with avail- able meteorological data suggests that abrupt deuterium excess fluctuations occurring in 1940, 1972 and 1981 may reflect changes in local sea-ice extent, confirming pre- liminary results obtained over a short time period in two shallow firn cores from DSS. A long term deuterium excess record measured on DSS deep ice core covers the past millenium with an annual resolution (from year 900 to year 1850). This record shows an abrupt excess decrease starting in year about 900 and lasting about 200 years, fol- lowed by a progressive excess increase until year 1500 and a progressive decrease until 1850. Superimposed onto these long term trends, the record presents rapid fluctuations which spectral analysis exhibits typical Antarctic Circumpolar Wave periodicities.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.1174M