Variability of chemical and physical parameters of aerosol in the Antarctic troposphere

Atmospheric aerosols are chronologically archived in polar ice cores by deposition processes. In principle, investigation of these signals in ice cores offers the opportunity to support the reconstruction of the history of the Earth´s climate. The entry of aerosols to the ice shields is subject of natural variability both at long (e.g. glacial-interglacial) and short (e.g. seasonal) time scales. Information on changes in source strength and transport pathways can be deduced from analysing these signatures. The knowledge of recent aerosol composition and deposition processes is an essential requirement for interpretation of polar ice cores in terms of climate history. This work focuses on spatial and temporal variabilities of the chemical composition of tropospheric aerosol and precipitation, as well as the columnar aerosol optical depth at the German research stations Neumayer, a coastal Antarctic site, and Kohnen located in continental Antarctica in the time period from 1999 to 2002. To obtain information on these variabilities, aerosol and snow samples were investigated regarding their ionic composition at Kohnen Station during austral summer. Investigated ions were MSA:sup:-:/sup: resp. CH3SO3:sup:-:/sup:, Cl:sup:-:/sup:, NO3:sup:-:/sup:, SO4:sup:2-:/sup:, Na:sup: :/sup:, NH4:img:=plus.gif:/img: , K:img:=plus.gif:/img: , Mg:sup:2:/sup::img:=plus.gif:/img: and Ca:sup:2:/sup::img:=plus.gif:/img: . At Neumayer Station the characterisation of the ionic composition and the concentration of some selected trace elements (Li, Sr, Al, Se, Rb, Mn, Fe, V, Cr, Pb and Co) was conducted throughout a year. During austral summer the columnar aerosol optical depth and hence the number and volume distribution of Antarctic aerosol, averaged over the total air column, was quantified both at Neumayer Station and at Kohnen Station by means of sun photometer measurements