On the curious case of the recent decade, mid-spring precipitation deficit in central Europe

M Ionita,O Rakovec,R Kumar,V Nagavciuc

doi:10.1038/s41612-020-00153-8

Abstract

Central Europe has experienced a severe drought almost every April for the last 14 years consecutively, driven by record high temperatures, low flows, high evapotranspiration, and high soil moisture deficit. The dynamic of this recent and recurrent mid-spring dryness is not yet understood. Here we show that the period 2007–2020 was characterized by a reduction of ~50% of the usual April rainfall amount over large areas in central Europe. The precipitation deficit and the record high temperatures were triggered by a multiyear recurrent high-pressure system centered over the North Sea and northern Germany and a decline in the temperature gradient between the Arctic region and the mid-latitudes, which diverted the Atlantic storm tracks northward. From a long-term perspective, the precipitation, temperature, and soil moisture anomalies observed over the last 14 years have reached the highest amplitudes over the observational record. Our study provides an in-depth analysis of the hydroclimate extremes in central Europe over the last 140 years and their atmospheric drivers, enabling us to increase our dynamical understating of long-term dry periods, which is vital to enhance forecasting and mitigation of such events.

Highlights

Hydroclimate variability affects natural and human systems globally, and extreme events such as floods, droughts, and heatwaves can alter ecosystem functioning, disrupt food production and security[1,2], significantly impact ecology and carbon sequestration[3,4], affect water availability[5], damage human settlements and increase mortality[6]
In April, over central Europe is due to a combination of extremely low precipitation, extremely high temperature, depleted soil moisture and a significant increase in evapotranspiration, which in turn have led to record low flows over the central European Rivers[69]
The E-OBS dataset is based on the of anticyclonic weather types and with a multiyear persistence of a European Climate Assessment and Dataset station information (ECA&D), high-pressure system centered over the North Sea and Germany, flanked by a low-pressure system over the central North Atlantic basin and a low-pressure system over western Siberia

Summary

Introduction

Hydroclimate variability affects natural and human systems globally, and extreme events such as floods, droughts, and heatwaves can alter ecosystem functioning, disrupt food production and security[1,2], significantly impact ecology and carbon sequestration[3,4], affect water availability[5], damage human settlements and increase mortality[6]. To test if the prevailing largescale circulation played a role in the extreme precipitation deficit and high temperatures over the period 2007–2020, we computed the large-scale atmospheric circulation anomalies during April over the last 14 years (Fig. 3a), with respect to the climatological period 1961–1990 (see Methods).

Results

Conclusion