Air content along the Greenland Ice Core Project core: A record of surface climatic parameters and elevation

We present here measurements of the air content of the ice, V, performed along the Greenland Ice Core Project (GRIP) ice core. The main features of the long-term trends are (1) a decrease of 13% between the last glacial maximum (LGM) and the earliest part of the Holocene, and (2) an increase of 8% during the Holocene. The results are discussed in terms of changes in atmospheric pressure, surface elevation and porosity at close-off. The V record contains a significant signal of past changes of surface elevation in qualitative agreement with ice sheet modeling simulations. It suggests a thickening of central Greenland during the transition from the LGM to the early Holocene, and a significant thinning through the Holocene period. It also stresses the large influence on past V variations of changes in ice porosity, which are not explained by the present-day spatial relationship with temperature and may reflect changes in other surface climatic parameters (like precipitation seasonality or wind stress). The potential role of temporal variations of atmospheric pressure patterns is also evaluated. Air content results in the GRIP ice older than 110 ka indicate values approximately in the same range as those observed during the last 40,000 years, with generally higher air content corresponding to isotopically warmer ice.

[1]  Gary D. Clow,et al.  Temperature, accumulation, and ice sheet elevation in central Greenland through the last deglacial transition , 1997 .

[2]  E. Brook,et al.  CH4 and δ18O of O2 records from Antarctic and Greenland ice: A clue for stratigraphic disturbance in the bottom part of the Greenland Ice Core Project and the Greenland Ice Sheet Project 2 ice cores , 1997 .

[3]  C. Ritz,et al.  Sensitivity of a Greenland ice sheet model to ice flow and ablation parameters: consequences for the evolution through the last climatic cycle , 1996 .

[4]  W. Dansgaard,et al.  Greenland palaeotemperatures derived from GRIP bore hole temperature and ice core isotope profiles , 1995 .

[5]  Richard B. Alley,et al.  Large Arctic Temperature Change at the Wisconsin-Holocene Glacial Transition , 1995, Science.

[6]  C. Ritz,et al.  Greenland under changing climates: sensitivity experiments with a new three-dimensional ice-sheet model , 1995 .

[7]  D. Raynaud,et al.  A new device for the measurement of air content in polar ice , 1995, Journal of Glaciology.

[8]  K. Hutter,et al.  Polythermal three-dimensional modelling of the Greenland ice sheet with varied geothermal heat flux , 1995, Annals of Glaciology.

[9]  V. Lipenkov,et al.  Air content paleo record in the Vostok ice core (Antarctica): A mixed record of climatic and glaciological parameters , 1994 .

[10]  R. Alley,et al.  Sensitivity of the ice-divide position in Greenland to climate change , 1994 .

[11]  J. Jouzel,et al.  Evidence for general instability of past climate from a 250-kyr ice-core record , 1993, Nature.

[12]  R. Souchez.  Climate instability during the last interglacial period recorded in the GRIP ice core , 1993 .

[13]  D. Etheridge,et al.  Physical and climatic parameters which influence the air content in polar ice , 1992 .

[14]  N. Reeh,et al.  The Greenland ice sheet through the last glacial-interglacial cycle , 1991 .

[15]  Philippe Huybrechts,et al.  The Greenland ice sheet and greenhouse warming , 1991 .

[16]  Jérôme Chappellaz.  Etude du méthane atmosphérique au cours du dernier cycle climatique à partir de l'analyse de l'air piégé dans la glace antarctique , 1990 .

[17]  T. Kameda,et al.  Thinning of the Ice Sheet Estimated from Total Gas Content of Ice Cores in Mizuho Plateau, East Antarctica , 1990, Annals of Glaciology.

[18]  S. Herron,et al.  Derivation of paleoelevatio ns from total air content of two deep Greenland ice cores , 1987 .

[19]  B. Stauffer,et al.  Age difference between polar ice and the air trapped in its bubbles , 1984, Nature.

[20]  D. Raynaud,et al.  Air Content Of The Byrd Core And Past Changes In The West Antarctic Ice Sheet , 1982, Annals of Glaciology.

[21]  D. Raynaud,et al.  Total gas content and surface elevation of polar ice sheets , 1979, Nature.

[22]  D. Raynaud,et al.  Ice Flow Along an I.A.G.P. Flow Line and Interpretation of Data From an Ice Core in Terre Adélie, Antarctica , 1979, Journal of Glaciology.