Variations in the depositional fluxes of cosmogenic beryllium on short time scales

We examined the concentrations and fluxes of 7Be and 10Be at three different sites, Greenland snow pit Dye3, Jungfraujoch and Dübendorf (both Switzerland, high and low altitude sites). The fluxes of both beryllium isotopes and the fluxes of SO4, NO3, NH4 and Ca were used to perform a principal component analysis (PCA) to find common variances in the deposition signal. At all three sites we find the same first principal component and similar patterns in deposition signals. At Dübendorf 90% of the 7Be and 80% of the 10Be variance in the depostion signal can be explained by the variance of SO4, NO3, NH4 and Ca, grouped into 2 components. At Jungfraujoch only 40% of the 7Be and 65% of the 10Be variance in the depostion signal can be explained by the same constituents. Furthermore, the different place of origin of deposited 7Be and 10Be can be found in the variance signals. A preferred attachment of cosmogenic berylium to SO4 could not be found.

► Different depositional processes are found in the cosmogenic 7Be and 10Be fluxes. ► A cleaning mechanism can be found at all three sites. ► 7Be at low altitude Swiss site shows a tropospherical depositional pattern. ► 10Be in Swiss low altitude site shows tropospherical and stratospherical deposition. ► The beryllium deposition pattern at high Swiss altitude is mainly stratospherical.