Lead


Lay summary

In orderto place recent climate change in a longer term context the reconstruction ofclimatic variations on annual, interannual, and decadal time scales of the last1000 years is a priority target in current climate research. This project aims to reconstruct differentclimate parameters using an ice core from a high-alpine glacier at a verycontinental site with low data coverage, the Altai mountain range in Central Asia.

In a previousproject 4140m asl, 48°39.338’N, 90°50.826’E) was selected as drilling site. During the oneweek spent on the glacier (3-10 July 2009) we extracted a 72 m ice core tobedrock and a 52 m parallel core. Ground penetrating radar data showed athickness of about 70 m and smooth bedrock at the drilling site. The surfaceand bedrock geometry survey suggest low ice velocities and indicate that theselection of the drilling site was optimal. Ice temperatures measured in theborehole range from -12.6 to -13.8°C, implying that percolating melt waterrefreezes within the top layers. Thus the glaciochemical records should be wellpreserved. Tsambagarav range (one of the icecaps in the

Up to nowwe have analyzed the upper 31 m, corresponding to 20 m waterequivalent (weq) ofthe 72 m ice core for major ions and stable isotopes (d18Pbwas used. Accumulation calculated from the different dating methods correspondsto 0.33 m weq/year. The low accumulation suggests that the ice core containsabout one millennium of climatic information including the Medieval Warm Periodand the Little Ice Age. 210H maximum and 3O), and a few sample for black carbonconcentration. Preliminary dating was performed by annual layer counting of theammonium and formate concentration, which show the strongest seasonalvariation. In addition, nuclear dating of the 1963

The mainobjectives of this follow-up project are to complete the geochemical analysisof the lowest 41 m of the 72 m Tsambagarav ice core, to finalise the dating ofthe entire core, to reconstruct temperature, precipitation, black carbonconcentration, and air pollution, and to provide key information aboutmagnitude and spatial patterns of climate change in this area of Central Asia.This project is a collaborative effort between the Analytical Chemistry Groupof the Laboratory of Radiochemistry and Environmental Chemistry, Paul ScherrerInstitut and University of Bern, the Department of Geosciences of the University of Fribourg,Switzerland, and theInstitut for Water and Environmental Problems SB RAS, Barnaul, Russia.