Stable isotopes in cave ice suggest summer temperatures in East-Central Europe are linked to AMO variability

Abstract

Abstract. The climate of East-Central Europe (ECE) is the result of the combination of influences originating in the wider North Atlantic realm, the Mediterranean Sea and Western Asia/Siberia. Climate models suggest that these competing influences will result in difficult to predict responses to the ongoing climatic changes, thus making mitigation and adaptation strategies challenging to devise and implement. Previous studies have shown that the complex interplay between the large-scale atmospheric patterns across the region result in strongly dissimilar summer and winter conditions on time scales ranging from decades to millennia. To put these into a wider context, long term climate reconstructions are required, but, largely due to historical reasons, these are lacking in ECE. We address these issues by presenting a high resolution, precisely dated record of summer temperature variations during the last millennium in ECE, based on stable isotopic analysis performed on a 4.84 m long ice core extracted from Focul Viu Ice Cave (Western Carpathians, Romania). The data shows little summer temperature differences between the Medieval Warm Period and the Little Ice Age on centennial scales, but with well-expressed minima and maxima occurred synchronously with periods of low and high solar activity. Further, summer temperatures fluctuated with a periodicity similar to that of the Atlantic Multidecadal Oscillation, suggesting that solar variability-induced climatic changes were transferred locally by atmospheric processes. Contrary to summer temperatures, winter ones show stronger contrast between the MWP and LIA, thus suggesting that the later were likely an expression of winter climatic conditions.