Long-term changes in the acid and salt concentrations of the Greenland Ice Core Project ice core from electrical stratigraphy

Wolff, Eric W.; Moore, John C.; Clausen, Henrik B.; Hammer, Claus U.; Kipfstuhl, Josef; Fuhrer, Katrin. 1995 Long-term changes in the acid and salt concentrations of the Greenland Ice Core Project ice core from electrical stratigraphy. Journal of Geophysical Research: Atmospheres, 100 (D8). 16249-16263. 10.1029/95JD01174

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Official URL: http://dx.doi.org/10.1029/95JD01174

Abstract/Summary

Continuous electrical records covering a climatic cycle are presented for the Greenland Ice Core Project deep ice core from Greenland. Electrical conductivity measurement (ECM) measures the acid content of the ice, and the dielectric profile (DEP) responds to acid, ammonium, and chloride. All features seen can be explained by chemical changes in the ice, and there is no evidence so far for any major change in electrical response with depth or age of the ice. Both records are dominated by the acidity of the ice which varies strongly from acidic in warm periods to alkaline in cold periods, controlled by neutralization by alkaline dust (calcareous and other mineral dust). When Ca is low, the acidity (mainly nitric acid) has a fairly constant background level throughout the cycle, with slightly lower values in ice believed to be from the last interglacial. Ca has to rise only slightly to neutralize the available acidity, so that acidity is a highly nonlinear reflection of climate changes. If neutralization occurred in the aerosol (rather than in the ice), then the number of cloud condensation nuclei over parts of the northern hemisphere could have been reduced, leading to reduced cloud albedo. This nonlinear feedback may have some importance for modeling of climate change. When both acid and ammonium levels are low, the DEP signal can be used to give a rapid indication of chloride trends.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/95JD01174
Programmes:	BAS Programmes > Pre 2000 programme
ISSN:	0148-0227
Date made live:	17 Jan 2017 11:31 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/515901

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/95JD01174

Programmes:

BAS Programmes > Pre 2000 programme

ISSN:

0148-0227

Date made live:

17 Jan 2017 11:31 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/515901