Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 1 2 2005 10.5194/cpd-1-169-2005 http://www.clim-past-discuss.net/1/169/2005/ http://www.clim-past-discuss.net/1/169/2005/cpd-1-169-2005.html http://www.clim-past-discuss.net/1/169/2005/cpd-1-169-2005.pdf 169 192 2005-09-22 Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes) P. Ginot C. Kull U. Schotterer M. Schwikowski H. W. Gäggeler Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland Paul Scherrer Institute, 5232 Villigen PSI, Switzerland PAGES International Project Office, Sulgeneckstrasse 38, 3007 Bern, Switzerland Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l., 30°08' S, 69°55' W) was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods) in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Under certain assumptions the chemical record along the ice core may be applied to reconstruct the history of such secondary processes. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq) and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation may exhibit a correlation with the Southern Oscillation Index (SOI). The deepest part of the ice record shows a time discontinuity; its age is unknown.