1. A 500 year palaeo record of sulphate and mineral dust from an Alpine ice core (Colle Gnifetti, Swiss Alps) M. Schwikowski 1, H.W. Gäggeler 1,2, U. Schotterer 2 1 Paul Scherrer Institute, Switzerland 2 Department of Chemistry and Biochemistry, University of Berne, Switzerland

2. Motivation  Reconstruction of local and regional climate and atmospheric parameters  Documentation of the effects of anthropogenic emissions

3. The ice core  Drilling site: Colle Gnifetti glacier saddle at 4450 m asl in the Monte Rosa area  Length: 124 m (bedrock)  Accumulation rate: 0.3 m water equiv. y -1  Cold glacier: firn temperatures << 0°C

4. Location

5. Time period accessible by this ice core Dating error: ± 2 years Dating error: ± 20 years

6. Mineral dust tracer Ca 2+ 1977 Saharan dust event

7. Mineral dust record Extrem events: Saharan dust 2529 samples (5 per year) 1977 1937 1901

8. Mineral dust record: long term trend Increased Ca 2+ from 1450 to 1620 (LIA?) 5-year averages Little Ice Age in NH: cold, dry, increased atmospheric circulation

9. 5-year averages Sea salt record ( Strength of Westerlies ) No trend

10. nssSulphate record Anthropogenic emissions, Saharan dust

11. nssSulphate trend increased concentrations from 1870-1970 5-year averages

12. Trend in nssSO 4 2- /Ca 2+ ratio Change in mineral dust source or SO 2 emissions?

13. Source contribution to SO 4 2- (  eq L -1 ) PeriodTotalSea salt Mineral dust exSO 4 2- NaturalAnthrop. Industrial 1963-1981 14.70.23 (2%) 1.92 (13%) 0.98 (6%) 11.6 (79%) Pre-industrial 1750-1870 2.710.19 (7%) 1.54 (57%) 0.98 (36%) -

14. Oldest ice

15. Conclusion  No change in frequency of major Saharan dust transports  From 1450 to 1620 A.D. increased input of mineral dust and lower nssSO 4 2- /Ca 2+ ratios (probably related to LIA)  No change in strength of Westerlies  Change in area of mineral dust source (and probably in pre-industrial SO 2 emissions)