NOAA/WDS Paleoclimatology - The European Russia Drought Atlas (ERDA) Reconstruction of PDSI from 1400 - 2016 CE

We present a new drought atlas for the East European or Russian Plain extending from eastern Europe to the Ural Mountains: the European Russia Drought Atlas or ERDA. Like the Old World Drought Atlas (OWDA) for the Euro-Mediterranean region, the ERDA is a one-half degree gridded reconstruction of summer Palmer Drought Severity Indices estimated from a network of annual tree-ring chronologies in European Russia and surrounding countries. Ensemble point-by-point regression was used to generate the ERDA with the identical protocols used for developing the OWDA. Split calibration/validation tests of the ERDA indicate that it has significant skill over most of its domain and is more skillful than the OWDA over their joint domains in western Russia. Comparisons to historical droughts over European Russia further support the ERDA's overall validity. The ERDA has been spatially smoothed and infilled using a local regression method to yield a spatially complete drought atlas back to 1400 CE. EOF analysis indicates that there are three principal modes of hydroclimatic variability in the ERDA. After Varimax rotation, these modes correlate significantly with independent climate data sets extending back to the late 19th century in a physically interpretable way and relate to atmospheric circulation dynamics of droughts and heatwaves over European Russia based on more recent instrumental data.