Simulated European stalagmite record and its relation to a quasi-decadal climate mode

A synthetic stalagmite δ ¹⁸O record for the Bunker Cave (51° N, 7° E) is constructed using a combined climate–stalagmite modelling approach where we combine an atmospheric circulation model equipped with water isotopes and a model simulating stalagmite calcite δ ¹⁸O values. Mixing processes in the soil and karst above the cave represent a natural low-pass filter of the speleothem climate archive. Stalagmite δ ¹⁸O values at Bunker Cave lag the regional surface climate by 3–4 yr. The power spectrum of the simulated speleothem calcite δ ¹⁸O record has a pronounced peak at quasi-decadal time scale, which is associated with a large-scale climate variability pattern in the North Atlantic. Our modelling study suggests that stalagmite records from Bunker Cave are representative for large-scale teleconnections and can be used to obtain information about the North Atlantic and its decadal variability.