Réf. Matulla & al. 2008 - A

Référence bibliographique complète

MATULLA, C., W. SCHOENER, H. ALEXANDERSSON, H.VON STORCH, WANG, X.L. 2008. European Storminess: Late 19th Century to Present, Climate Dynamics, 31(2-3), 125–130. [Etude en ligne]

Abstract: Annual and seasonal statistics of local air pressure characteristics have already been used as proxies for storminess across Northern Europe. [This study] present an update of such proxies for Northern Europe and an unprecedented analysis for Central Europe which together considerably extends the current knowledge of European storminess. Calculations are completed for three sets of stations, located in North-Western, Northern and Central Europe. Results derived from spatial differences (geostrophic winds) and single station pressure changes per 24 h support each other. Geostrophic winds’ high percentiles (95th, 99th) were relatively high during the late nineteenth and the early twentieth century; after that they leveled off somewhat, to get larger again in the late twentieth century. The decrease happens suddenly in Central Europe and over several decades in Northern Europe. The subsequent rise is most pronounced in North-Western Europe, while slow and steady in Central Europe. Europe’s storm climate has undergone significant changes throughout the past 130 years and comprises significant variations on a quasi-decadal timescale. Most recent years feature average or calm conditions, supporting claims raised in earlier studies with new evidence. Aside from some dissimilarity, a general agreement between the investigated regions appears to be the most prominent feature. The capability of the NAO index to explain storminess across Europe varies in space and with the considered period.

Mots-clés

 

 

Organismes / Contact

Climate Research Division, Environment Canada, 4905 Dufferin Street, Toronto, ON, M3H 5T4, Canada (christoph.matulla@zamg.ac.at)
• Central Institute for Meteorology and Geodynamics, Vienna, Austria
Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
• Institute for Coastal Research, GKSS, Geesthacht, Germany

 

(1) - Paramètre(s) atmosphérique(s) modifié(s)

(2) - Elément(s) du milieu impacté(s)

(3) - Type(s) d'aléa impacté(s)

(3) - Sous-type(s) d'aléa

 

 

 

 

 

Pays / Zone

Massif / Secteur

Site(s) d'étude

Exposition

Altitude

Période(s) d'observation

Europe du Nord et Europe centrale (nord des Alpes)

 

 

 

 

 1880s to 1990s

 

(1) - Modifications des paramètres atmosphériques

Reconstitutions

 

Observations

 

Modélisations

 

Hypothèses

 

 

Informations complémentaires (données utilisées, méthode, scénarios, etc.)

 

 

(2) - Effets du changement climatique sur le milieu naturel

Reconstitutions

 

Observations

 

Modélisations

 

Hypothèses

 

 

Sensibilité du milieu à des paramètres climatiques

Informations complémentaires (données utilisées, méthode, scénarios, etc.)

 

 

 

(3) - Effets du changement climatique sur l'aléa

Reconstitutions

 

Observations

The present study significantly extends the explored regions (e.g. Alexandersson et al. 1998; Alexander et al. 2005) into Central Europe. Thereby it allows for an assessment of European storminess on a more general scope. The increase in storms throughout Northern Europe from the 1960s to the 1990s raised public concern. This diminished once storm levels decreased in the mid 1990s (Alexandersson et al. 1998).

This study provides updated information relevant in determining whether storminess is once again on the incline or has settled to more calm conditions. Major findings are listed as follows in italics:

The storm climate in Europe has undergone considerable changes throughout the past 130 years and shows significant variation on a quasi-decadal timescale

The bulk chronology since the 1880s may be described as residing at high levels of storminess around the early twentieth century, followed by a decline to rather calm conditions and a rise afterwards. The decline appears suddenly in Central Europe and over several decades in Northern Europe. Findings for Northern Europe are in accordance with WASA (1998), Alexandersson et al. (1998) and Bärring and von Storch (2004). Alexander et al. (2005) showed that the later part of the twentieth century is marked by increasing storminess, which is in line with the present findings. However, the much longer period used here reveals that this increase from the 1960s to the 1990s starts from particularly calm conditions and ends at levels of storminess, which are comparable to those of the turn from the nineteenth to the twentieth century. Recent years have brought no substantial change for Northern Europe and are hence collaborating claims raised by Alexandersson et al. (2000). For Central Europe we are not aware of any comparable assessment of storminess yet, so findings appear new. Highest levels of Central European storminess are reached after a steep incline from the 1880s at the beginning of the twentieth century. After a rapid fall to below average values storminess slowly inclines to average conditions towards the end of the century.

Most recent years are characterized by a return to average or calm conditions

Alexandersson et al. (2000) regarded a breakdown of the increase in Northern Europe storminess since the mid 1990s as likely, though their claim referred to data that only ranged till 1998. Thus it is advantageous to update the analysis and to determine if the claim can be adapted to the most recent years as well. We found it applies. In Central Europe the geostrophic wind indicates some years of enhanced storminess in the late 1990s, but more recent years were calm too.

Storminess in Northern and Central Europe share their main characteristics

The aforementioned bulk run of storminess through the past 130 years is to be found in Northern Europe and Central Europe. An EOF analysis reveals the leading EOF as being representative of the commonness among the investigated stations and its time coefficient tracks the broad evolution. A rotated EOF analysis and a cluster analysis show that stations in Central Europe can still be separated from those in Northern Europe. Together that means similarities amongst the stations are an important feature, but Central European stations can still be distinguished from those in Northern Europe.

The ability of the NAO index to explain storminess across Europe depends on the region and period under consideration

The NAO index is capable of explaining some variability in North-Western Europe throughout the last decades (Alexander et al. 2005), but fails to explain earlier storminess (Alexandersson et al. 1998). In Central Europe the link over the past 130 years is looser still. So, even though the sign of the correlation between the NAO index and storminess attributes negative NAO index values to higher storminess in Central Europe while positive values come along with enhanced storminess in Northern Europe, the NAO index is not very helpful to describe storminess over the past 130 years. This highlights the importance of long-term, high-quality climatological datasets for statistical analysis in climate assessment. Datasets used in this study put the perceived increase in Northern Europe’s storminess during the later part of the twentieth century into perspective, showing that levels of storminess in the 1990s fit those of the late nineteenth, early twentieth century. This is in line with Bärring and von Storch (2004), who showed for Lund and Stockholm that storminess has not significantly changed over the past 200 years.

Modélisations

 

Hypothèses

 

 

Paramètre de l'aléa

Sensibilité des paramètres de l'aléa à des paramètres climatiques

Informations complémentaires (données utilisées, méthode, scénarios, etc.)

Air pressure / Geostrophic winds

 

Pressure data from Northern Europe and their quality are detailed in Alexandersson et al. (1998) and the update to 2005 is processed accordingly. Stations used in Central Europe are Kremsmünster (1874–2005) and Vienna (Hohe Warte, 1872–2005) in Austria, and Klementinum (1874–2001) plus Karlov (1921–2005) in Prague, Czech Republic.

 

(4) - Remarques générales

 

 

(5) - Syntèses et préconisations

 

Références citées :

Alexander LV, Tett S, Jonsson T (2005) Recent observed changes in severe storms over the United Kingdom and Iceland. Geophys Res Lett 32:L13704. doi:10.1029/2005GL022371

Alexandersson H, Schmith T, Iden K, Tuomenvirta H (1998) Long-term variations of the storm climate over NW Europe. Glob Atmos Ocean Syst 6:97–120.

Alexandersson H, Tuomenvirta H, Schmith T, Iden K (2000) Trends of stroms in NW Europe derived form an updated pressure data set. Clim Res 14:71–73.

Bärring L, von Storch H (2004) Scandinavian strominess since about 1800. Geophys Res Lett 31:L20202.

WASA (1998) Changing waves and storms in the northeast Atlantic. Bull Am Meteorol Soc 79:741–760.