Das Projekt "LAMODATE: Lakustrische Ablagerungen als Monitoren von Dynamik im Grenzbereich Atmosphaere-Erdoberflaeche - 1. Projektphase: Kalibration chemisch-physikalischer Tracer, Testgebietstudien" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule Zürich, Geologisches Institut durchgeführt. Leading Questions: Variations in the stable-isotope composition of Alpine and peri-Alpine surface waters are expected to ultimately reflect the different origins of the air masses (Atlantic vs. Mediterranean) - with superimposed factors such as seasonality- and altitude effects. Questions: - Is it possible, through calibration of the recent isotope patterns (and their extensions into the past via lacustrine proxy data) to reconstruct past changes in atmospheric circulation? - Is it possible through the calibration of annual varve deposits (thickness and grain-size parameters) to quantify local drainage characteristics (precipitation and ice-melt) and to follow them back beyond measured meteorological and hydrological records? Abstract: The project consists of two parts: I. Mittelland-lake sediments: their geochemical signal of climate change Oxygen isotope signatures in lake sediments provide information on past rainfall and atmospheric circulation pattern. Oxygen isotope curves from Baldeggersee and from Greifensee record distinct changes in precipitation since the end of the Little Ice Age. II. Alpine-lake sediments: their clastic response to climate change Sediments from the Engadine lakes store the Holocene erosion history of an alpine valley and the clastic sediment record documents the impact of glacial erosional activity on the alpine landscape evolution. Low sedimentation rates offer the opportunity to trace the erosional history throughout the Holocene. Complementary information: Water cycle processes leave characteristic signals in lacustrine sediments. However, more detailed information on the present natural variability is needed to obtain quantitative interpretations of climatic variations in the past. The scope of this project is to calibrate proxy-data in the present and to apply them to the interpretation of past climate changes. In the first phase of this project we will sample surface waters (rivers and lakes) and measure oxygen- and hydrogen isotopic compositions in order to obtain an insight into integration processes and patterns for the different climatic regions of Switzerland. We will also collect short sediment cores from selected lakes in order link modern proxy data to their environmental controls and to follow the most recent evolutionary trends. This calibration should then enable the objective interpretation of stable-isotope records preserved in sedimented lacustrine carbonates in terms of past climatic conditions. Clastic varves from lakes in the Engadine test-region will be used to determine variations of catchment runoff rates caused by changes in precipitation and/or temperature.