HR: 1340h
AN: C23A-0982    [Abstracts]
TI: Continuous Measurements of Air Content: First Results from the EDML Ice Core, Antarctica
AU: Freitag, J
AF: Alfred-Wegener-Institut, Columbusstrasse, Bremerhaven, 27568 Germany
AU: * Ruth, U
EM: uruth@awi-bremerhavne.de
AF: Alfred-Wegener-Institut, Columbusstrasse, Bremerhaven, 27568 Germany
AU: Kaufmann, P
AF: Univ. of Bern, Sidlerstrasse 5, Bern, 3112 Switzerland
AU: Kipfstuhl, S
AF: Alfred-Wegener-Institut, Columbusstrasse, Bremerhaven, 27568 Germany
AU: Raynaud, D
AF: LGGE, BP 96, St Martin d Heres, 38102 France
AB: The air content in cold glacier ice depends on the pore space volume and on local air pressure and temperature at the time of pore close-off. A new method to measure the air content of glacier ice has been developed and will be presented. The measurement has been integrated into the Continuous Flow Analysis set-up which is used for chemical profiling of the EPICA ice cores. It allows the continuous determination of the air content at high depth resolution (<1cm). The air content has been measured continuously in the deep ice core from Dronning Maud Land, Antarctica from 700 m to 2450 m depth, which corresponds to approx. 10 ka to 150 ka before present. First results indicate that the smoothed profile is not dominated by the 100 ka cycle but instead by the 40 ka insolation cycle. The high resolution record exhibits considerable variability of the air content even on the 1 cm scale. These variations may partly be seasonal, and we will discuss the possible importance of different causalities that may influence the air content of glacier ice. The small scale variations of air content may suggest heterogeneous pore close-off and eventually may aid its reconstruction.
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting