caa a22 4500 605472467 CHVBK 20210128100338.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00382-015-2521-5 doi (NATIONALLICENCE)springer-10.1007/s00382-015-2521-5 δ18O values of cave drip water: a promising proxy for the reconstruction of the North Atlantic Oscillation? [Elektronische Daten] [Simon Mischel, Denis Scholz, Christoph Spötl] We present cave monitoring data and two drip water δ18O models for the Herbstlabyrinth-Adventhöhle (HL) cave system, Germany. Winter climate of the cave region is influenced by the North Atlantic Oscillation (NAO), as documented by the positive correlations between winter temperature, winter rainfall δ18O values and the winter NAO index. Cave monitoring data show that recharge of the aquifer at the HL cave system mainly occurs during winter months, confirming our drip water model, which calculates recharge as the difference between precipitation and potential evapo-transpiration. Cave drip water from the HL cave system should, thus, be a sensitive proxy for reconstruction of the NAO. The infiltration models accounting for mixing effects occurring in the karst aquifer show a very good agreement with the monitoring data. Comparison of the modelled and the monitored drip water δ18O values suggests a mean residence time of the water in the aquifer of 12months and a transmission time of 10months. Using these parameters, a long-term dataset from the nearby meteorological station Frankfurt am Main and the rainfall δ18O data from our monitoring program, we model the δ18O values of the cave drip water for the last 144years. Despite of the favourable conditions of the HL cave system for NAO reconstruction, the modelled drip water δ18O time series only shows a moderate correlation with the winter NAO index (r=0.33). The major reason for the relatively low correlation is the substantial contribution of precipitation from the remaining seasons to the drip water, for instance, due to heavy precipitation events occurring during summer. These rainfall events bias the seasonality of infiltration and weaken the winter NAO signal recorded in the drip water δ18O values. Reconstruction of the NAO from speleothems is, thus, challenging, in particular considering further complications arising from chronological uncertainties and calcite precipitation under conditions deviating from isotopic equilibrium. These problems may, at least in part, be avoided by multi-proxy studies of annually laminated stalagmites. Springer-Verlag Berlin Heidelberg, 2015 NAO nationallicence Cave monitoring nationallicence Stable isotopes nationallicence Modelling nationallicence Mischel Simon Institute for Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany aut Scholz Denis Institute for Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany aut Spötl Christoph Institut für Geologie, Leopold-Franzens-Universität, Innrain 52, 6020, Innsbruck, Austria aut Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 3035-3050 0930-7575 45:11-12<3035 2015 45 382 https://doi.org/10.1007/s00382-015-2521-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-015-2521-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mischel Simon Institute for Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany aut NATIONALLICENCE 700 1- Scholz Denis Institute for Geosciences, University of Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany aut NATIONALLICENCE 700 1- Spötl Christoph Institut für Geologie, Leopold-Franzens-Universität, Innrain 52, 6020, Innsbruck, Austria aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 3035-3050 0930-7575 45:11-12<3035 2015 45 382