Browsing by Autor "Margit Schwikowski"

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    Climate variability during the last 1000 years inferred from Andean ice cores: A review of methodology and recent results
    (Elsevier BV, 2008) Françoise Vimeux; Patrick Ginot; Margit Schwikowski; Mathias Vuille; Georg F. Hoffmann; Lonnie G. Thompson; U. Schotterer
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    Potential for climate variability reconstruction from Andean glaciochemical records
    (Cambridge University Press, 2002) Patrick Ginot; Margit Schwikowski; U. Schotterer; Willibald Stichler; H. W. Gäggeler; Bernard Francou; Robert Gallaire; Bernard Pouyaud
    Abstract In order to select glacier sites suitable for the reconstruction of short-term climate variability, chemical constituents of shallow cores from Chimborazo, Ecuador, Illimani, Bolivia, and Cerro Tapado, Chile, were analyzed to determine if they represent the climate and atmospheric conditions of the particular area. Pronounced variations were observed in the Chimborazo core, which were attributed to the seasonal occurrence of wet and dry periods. Using chemical tracers, the Pacific and the Amazon basin were identified as the two principal sources of atmospheric moisture. In the Illimani record, seasonality is obvious but is less regular than in the Chimborazo core. Chemical tracers point to the Amazon basin as a moisture source. Post-depositional sublimation masks a possible atmospheric signal in the glaciochemical records from Cerro Tapado. the arid conditions and a prevailing high condensation level also cause little variability in the stable-isotope content. Irregular, more negative δ 18 O values occur during the humid phases of El Niño events. Despite alterations due to sublimation, chemical tracers indicate the Pacific Ocean as a main moisture source for precipitation preserved on Glaciar CerroTapado.