6000 years of winter climate variability revealed by a speleothem record from East-Central Europe

Holocene reconstructions of winter climate in East-Central Europe (ECE) are scarce, although several studies have brought more seasonal insights through the study of pollen in lake sediments, δ¹⁸O and deuterium excess from an ice cave deposit, as well as speleothem trace elements.

Here we present the δ¹⁸O record of stalagmite PU-2 from Urşilor Cave (W Romania) that could shed further light onto ECE Holocene hydroclimate variability for the past 6000 years. This previously published stalagmite benefits now from a more detailed age-depth model and an increased temporal resolution, to an average of 15 years across the whole record. More importantly, following recent monitoring studies, it was concluded that the δ¹⁸O signal in the cave drip water is representative of winter climate conditions.

In East-Central Europe there is a significant correlation between the winter temperature and the East Atlantic teleconnection pattern (EA), as this region witnesses higher than average temperatures during the positive phase of EA. The North Atlantic Oscillation teleconnection pattern (NAO) is known to modulate winter precipitation in the European realm, and many NAO reconstructions have sought to identify its variability in the past.

To investigate the drivers behind winter climate dynamics in the region surrounding the cave and across Europe, we compare our data with other speleothem winter temperature and rainfall records from Europe and the Levant. Further, we examine their variability on a complex time-evolving relationship with the coupled NAO/EA patterns.