Anomalies in Moisture Supply during the 2003 Drought Event in Europe: A Lagrangian Analysis

Milica Stojanovic,Raquel Nieto,Anita Drumond,Luis Gimeno

doi:10.3390/w10040467

Abstract

In the last few decades, many studies have identified an increasing number of natural hazards associated with extreme precipitation and drought events in Europe. During the 20th century, the climate in Central Europe and the Mediterranean region was characterised by an overall temperature increase, and the beginning of the 21st century has been marked by severe and prolonged drought events. The aim of this study is to analyse variations in the moisture supply during the 2003 drought episode that affected large portions of Europe. In order to better characterise the evolution of the episodes across the continent, separate analyses were performed for two spatial domains: Central Europe and the Mediterranean region. These regions were defined according to the 5th Intergovernmental Panel on Climate Change Assessment Report. For both regions, this drought episode was most severe from 1980 to 2015, according to the one-month Standardised Precipitation Evapotranspiration Index (SPEI-1) analysis, which was conducted using monthly precipitation and potential evapotranspiration data from the Climate Research Unit. Analyses of precipitation, potential evapotranspiration, pressure velocity at 500 hPa, and vertically integrated moisture flux were conducted to characterise the anomalous patterns over the regions during the event. A Lagrangian approach was then applied in order to investigate possible continental-scale changes in the moisture supply over the Central European and Mediterranean regions during 2003. This approach is based on the FLEXible PARTicle (FLEXPART) dispersion model, integrated with data from the European Centre for Medium-Range Weather Forecasts (ECMWF): the ECMWF Re-Analysis ERA-Interim. The results indicate that anomalous subsidence, increased evapotranspiration, and reduced precipitation predominated over both regions during the episode. The most intense reduction in the moisture supply over Central Europe was registered for the Mediterranean Sea (MDS) and the Central European region, while for the Mediterranean region, most intense reduction in the moisture supply was observed in the MDS and—in minor-scale—Gibraltar regions.

Highlights

Climate change is one of the major causes of global temperature increases and the variability of extreme events, including droughts [1]
We focus on the 2003 meteorological drought event that occurred in Europe, mainly affecting the Central European region (CEU) and the Mediterranean region (MED) (Figure 1)
Based on the same methodology that was applied by Stojanovic et al [36] in their regional study for the Danube River Basin, here we focus on investigating the extension of the 2003 drought conditions across Europe on a continental scale, using a more recent Climate Research Unit (CRU) dataset, for the period 1980–2015

Summary

Introduction

Climate change is one of the major causes of global temperature increases and the variability of extreme events, including droughts [1]. During the 20th century, the climate in Central Europe and the Mediterranean region was characterised by an overall temperature increase, and the beginning of 21st century has been marked by severe and prolonged drought events [2,3,4,5,6]. Droughts are part of the natural climate cycle. They commonly affect large areas, and are related to a prolonged lack of precipitation. It is possible to define a drought in

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