A new windstorm proxy from lake sediments: A comparison of geological and meteorological data from western Germany for the period 1965-2001

Abstract

The feasibility of detecting windstorm layers in lake sediments is explored by comparing quartz grain size data from a freeze core obtained from the Schalkenmehrener Maar (Eifel region, western Germany) to recent meteorological wind data. The Schalkenmehrener Maar is appropriate for such a calibration study because the morphological settings of the lake allow the conservation of windstorm layers (in particular, there is no fluvial sediment inflow) and long-term wind measurements are available from nearby stations. The age model for the uppermost 30 cm of the sediment core is based on measurements of 137 Cs and 210 Pb concentrations. An ultra-high-resolution grain size analysis is performed digitally on thin sections and reveals distinct 1-mm-thick layers with increased quartz grain content and sharp Gaussian grain size distributions, which are shifted to larger grain sizes compared to the normal lake sediment. In order to compare the occurrence of these layers with meteorological wind data, a windstorm index is developed, combining data from meteorological stations in the Eifel region and reanalyses from the European Centre for Medium-range Weather forecast. A statistical evaluation of matches between the windstorm index and the core's silt fraction data indicates that the sediment layers very likely coincide with the major windstorm events in the Eifel region during the last decades (six historical storm are identified). This pilot study identifies the main requirements and proposes a novel methodological approach for using sediment data from lakes with similar settings as the Schalkenmehrener Maar as a new proxy to reconstruct the windstorm record of the geological past. Copyright 2009 by the American Geophysical Union.