TY  - GEN
N2  - Speleothems are recognised as valuable palaeo climate archives. This has lead to an increasing number of analysed speleothem proxy time series from caves that are distributed on a global scale. In particular speleothem ?18O and ?13C time series are investigated. A hotspot of analysed speleothem proxy time series is Europe, which makes it possible to perform spatio-temporal coherency analysis of speleothem proxy time series. For this aim a method is developed that is based on Principal Component Analysis (PCA). The method is based on a Monte Carlo approach and accounts for the speleothem age uncertainty and the different temporal resolution of speleothem proxy time series. This method is applied to compilations of European speleothem ?18O and ?13C time series. It is demonstrated that the results of the PCA for the compiled ?18O time series can be interpreted as a temperature proxy and as a precipitation/hydrology proxy for the compilation of ?13C time series. Furthermore, it is showed that the spatio-temporal coherence between the analysed speleothem ?18O and ?13C time series varied with time. Moreover, a change of the predominant pattern is observed at 4.0 ka.
The second aim of this study is to analyse the change the observed speleothem ?18O gradient for European speleothems. A multi-box Rayleigh approach model is developed (Stable Isotope in Precipitation (SIP) model) that computes the stable isotope composition of precipitation, infiltrated water and calcite. The model is validated with measured precipitation ?18O and ?D values from the GNIP dataset. It is demonstrated that the SIP model agrees with the observed ?18O and ?D values for the analysed Central European and Northern European transect. Moreover, it is showed that the precipitation ?18O (?D) gradient depends on the North Atlantic Oscillation. This is interpreted as a change of the amount of moisture in the atmosphere for Central Europe. The application of the SIP model of palaeo climate speloethem ?18O gradients suggests that the climate was drier in the early- and mid-Holocene compared to present-day. In addition, the past ?18O gradients suggest a transition of the atmospheric circulation from a very negative NAO like pattern in the early-Holocene (11 ka) to a very positive NAO like pattern in mid-Holocene (4 ka) and that a reorganisation of the atmospheric circulation occurred at approximately 4 ka
when present-day atmospheric circulation established.
A1  - Deininger, Michael
TI  - The European Holocene Climate from the Speleothem?s View : Investigating spatio-temporal coherent changes in European speleothem proxy time series
AV  - public
Y1  - 2013///
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/16039/
ID  - heidok16039
ER  -