DEP-gamma-density bench used during the EPICA Dronning Maud Land pre-site survey


Contact
Diedrich.Fritzsche [ at ] awi.de

Abstract

To profile the ice cores being drilled from the EPICA Dronning Maud Land pre-site survey in terms of density and dielectric properties a combined analyses bench has been developed. All the firn and ice cores cored during the German activities, the ice cores brought to Europe from the surveys of the Nordic group and besides EPICA the German-Russian Sevemaya Zemlya core were analysed on the combined bench. 29 ice and firn cores with an added length of more than 1373 m passed through the bench. The yielded data and its interpretation are published in various journals, but the bench itself has not been described yet in the literature. Tue bench's new features are: (1) the combination of DEP and gamma-densimeter, (2) the adjustability of the core's position in the middle of the DEP electrodes and (3) the manageability of broken core in a setup with disposed core. With these special features the bench is a fast scanner for the determination of accumulation already in the field with improved DEP precision in the order of l%. This precision is exclusively achieved when remaining air gaps between the core and the electrodes are considered. Tue mathematical theory is lengthy, but the air gaps' effects will be illustrated with selected plots of calculated potential distributions within the electrodes. For the measurement the core is wrapped in a 20 micron thick plastic foil and suspended under a carrier. The carrier moves motor driven along a rail guide and stops at the scanners position - here gamma-densimeter and DEP - for the measurements to be taken. The paper's scope is to describe a fast precise scanner for accumulation determination and electrical profiles. Besides the detennination ofthose climatological parameters the dielectric profiles are input data for modeling radargrams and to test dielectric mixture models for snow, e.g. Looyenga's model. Some example datasets will be presented to illustrate the potentialities of the bench.



Item Type
Conference (Talk)
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Primary Division
Programs
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
Ice Cores and Climate, 19 Aug 2001 - 23 Aug 2001, Kangerlussuaq, Greenland.
Eprint ID
48951
Cite as
Wilhelms, F. , Oerter, H. , Frenzel, A. , Kipfstuhl, S. , Fritzsche, D. and Miller, H. (2001): DEP-gamma-density bench used during the EPICA Dronning Maud Land pre-site survey , Ice Cores and Climate, Kangerlussuaq, Greenland, 19 August 2001 - 23 August 2001 .


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