Early spring droughts in Central Europe: Indications for atmospheric and oceanic drivers

Early Springs (ES), March and April in particular, have been extremely dry in Central Europe in recent years, particularly from 2003 onwards. This is causing substantial impacts, foremost to agriculture, which is heavily dependent on sufficient moisture supply at the beginning growing season. However, the drivers of ES droughts are still not well understood. In this article, we investigate the temporal evolution of ES precipitation anomalies for the period 1860-2020 over Central Europe and the driving large-scale atmospheric circulation conditions. Two periods of ES drought conditions stand out, the most recent period (2005-2020) and another one during the middle of the 20th century (1926-1950) which show sustained negative precipitation anomalies in ES with only a few exceptions. The positive phase of the East Atlantic/Western Russia surface air pressure patterns is found as the main driver of ES precipitation deficit. Further analyses reveals an important role of positive western Atlantic sea surface temperature anomalies. These drive a Rossby wave response, resembling the positive phase East Atlantic/Western Russia pattern. Although the given evidence points towards internal multidecadal North Atlantic variability driving the warming patterns. Anthropogenic warming from enhanced greenhouse gas emissions cannot be discarded as additional forcing of the recent ES drought period. Early Springs (ES), March and April in particular, have been extremely dry in Central Europe in recent years. The positive phase of the East Atlantic/Western Russia surface air pressure patterns is found as the main driver of ES precipitation deficit. Further analysis reveal an important role of positive western Atlantic sea surface temperature anomalies. These drive a Rossby wave response, resembling the positive phase East Atlantic/Western Russia pattern.