Elemental ratios and enrichment factors in the tropospheric aerosol at Terra Nova Bay: methods of analysis and results for the coarse fraction, a progress report

The set of elemental concentration data (for Na, Mg, Cl, S, Ca, k, Si, Mn, Fe) corresponding to coarse fraction aerosol samples collected at Terra Nova Bay (Antarctica) during the 1993/94 summer season(1,2,3), as well as the results of their PCA analysis are considered. The problem of representing satisfactorily with a limited number of PCs, not only most of the total variance, but also the elemental concentrations, as well as the value of the S/Ca ratio, is considered. A method is presented, based on the notion of "virtual concentration", which allows to conclude that the use of a "minor" PC (PC2) (to which both S and Ca are correlated) is needed. PC2 appears marine in origin and is used, jointly with PC0 ("sea salt") component to evaluate the overall enrichment factors of elements S, Ca and K (2.48, 0.91, 3.54 respectively) with respect to the standard oceanic water composition. A possible interpretation of this results by means of a comparison with data of a single particle analysis(4) of samples collected in the Antarctic Peninsula is presented. No evidence of enrichment for the crustal elements Si, Mn,Fe is found in the marine components.