Reconstitution of August SPEI3 drought index based on the δ18O in tree-ring cellulose for the Eastern Carpathian, for the period 1331-2012CE

Here we report the reconstruction of the summer (June to August) Standardized Precipitation-Evapotranspiration Index (SPEI3), for the period 1331-2012CE, for eastern Europe, based on annually-resolved stable oxygen isotope ratios (δ18O) from Pinus cembra L. tree-ring cellulose from the Călimani Mountains, Romania. Variations of the δ18O values capture the August SPEI3 changes both at high and low frequencies (from interannual to multidecadal scales).

The palaeoclimate potential of stable isotopes in Pinus cembra L. (Swiss stone pine) tree-ring cellulose from the Călimani Mountains has been demonstrated by Nagavciuc et al. 2019 (DOI: 10.1002/joc.6349), showing that δ18O variability allows high-resolution paleoclimatic reconstructions over the eastern part of Europe, where few such reconstructions are available.