Temperature extremes in Europe: overview of their driving atmospheric patterns

C. Andrade,S. M. Leite,J. A. Santos

doi:10.5194/nhess-12-1671-2012

C. Andrade, S. M. Leite + Show 1 more

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https://doi.org/10.5194/nhess-12-1671-2012

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Abstract

Abstract. As temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation, is particularly pertinent and is discussed here for Europe and in the period 1961–2010 (50 yr). For this aim, a canonical correlation analysis, coupled with a principal component analysis (BPCCA), is applied between the monthly mean sea level pressure fields, defined within a large Euro-Atlantic sector, and the monthly occurrences of two temperature extreme indices (TN10p – cold nights and TX90p – warm days) in Europe. Each co-variability mode represents a large-scale forcing on the occurrence of temperature extremes. North Atlantic Oscillation-like patterns and strong anomalies in the atmospheric flow westwards of the British Isles are leading couplings between large-scale atmospheric circulation and winter, spring and autumn occurrences of both cold nights and warm days in Europe. Although summer couplings depict lower coherence between warm and cold events, important atmospheric anomalies are key driving mechanisms. For a better characterization of the extremes, the main features of the statistical distributions of the absolute minima (TNN) and maxima (TXX) are also examined for each season. Furthermore, statistically significant downward (upward) trends are detected in the cold night (warm day) occurrences over the period 1961–2010 throughout Europe, particularly in summer, which is in clear agreement with the overall warming.

Highlights

Europe has been experiencing strong extreme events over the last decades, including temperature extremes, namely cold spells and heat waves
Owing to the impacts temperature extremes have on human activities, water and energy supply (IPCC, 2008; Koch and Vogele, 2009; Forster and Lilliestam, 2010), agricultural resources (Ferris et al, 1998), forest fires (Pereira et al, 2005; Moriondo et al, 2006), and economy in general, their understanding is of utmost relevance for scientists and decision-makers, and for the whole society
As climate variability in Europe is strongly influenced by the variability of the large-scale atmospheric circulation, this study aims at understanding the links between the large-scale circulation in the Euro-Atlantic sector and the occurrences of temperature extremes in Europe, in winter, summer, spring and autumn

Summary

Introduction

Europe has been experiencing strong extreme events over the last decades, including temperature extremes, namely cold spells and heat waves. These extreme events, such as the 2003 and 2005 European heat waves (Schar et al, 2004; Trigo et al, 2005; Chase et al, 2006; Della-Marta et al, 2007; Santos et al, 2007; Luterbacher, 2010), the unusually cold and snowy/rainy winters of 2009 (central and western Europe) and 2010 (Wang et al, 2010; Andrade et al, 2011; Guirguis et al, 2011), had a great impact on many socioeconomic sectors throughout Europe, including increases in the mortality rates (WHO, 2003; Milligan, 2004; Poumadere et al, 2005; Robine et al, 2008).

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