The Mineral Dust Record in a High Altitude Alpine Glacier (Colle Gnifetti, Swiss Alps)

Abstract

Ice-core and snow-pit samples from a non-temperated glacier in the summit range of Monte Rosa, Swiss Alps (4450 m.a.s.l.) has been analyzed for total mineral dust and the size distribution of insoluble particulate matter in the size range 0.63-20 microns. Based on a 50 years-record Saharan dust accounts for two third of the mean mineral dust flux of 60 I'gcm-lyr-1 • Both, background and Saharan dust influenced samples show a distinct mode in the volume size distribution of insoluble particles over the optical active size range with a typical volume mean diameter of 2.5 and 4.5 I'm, respectively. These two size distribution categories are attributed to the insoluble fraction of the long lived back-ground aerosol and to the relatively short lived aerosol dominated by soil derived dust (i.e. ground-level aerosol in aride areas).