Projections of extreme storm surge levels along Europe

Michalis I Vousdoukas,Evangelos Voukouvalas,Luc Feyen,Alessio Giardino,Alessandro Annunziato

doi:10.1007/s00382-016-3019-5

Michalis I Vousdoukas, Evangelos Voukouvalas + Show 3 more

Open Access

https://doi.org/10.1007/s00382-016-3019-5

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Abstract

Storm surges are an important coastal hazard component and it is unknown how they will evolve along Europe’s coastline in view of climate change. In the present contribution, the hydrodynamic model Delft3D-Flow was forced by surface wind and atmospheric pressure fields from a 8-member climate model ensemble in order to evaluate dynamics in storm surge levels (SSL) along the European coastline (1) for the baseline period 1970–2000; and (2) during this century under the Representative Concentration Pathways RCP4.5 and RCP8.5. Validation simulations, spanning from 2008 to 2014 and driven by ERA-Interim atmospheric forcing, indicated good predictive skill (0.06 m < RMSE < 0.29 m and 10 % < RMSE < 29 % for 110 tidal gauge stations across Europe). Peak-over-threshold extreme value analysis was applied to estimate SSL values for different return periods, and changes of future SSL were obtained from all models to obtain the final ensemble. Values for most scenarios and return periods indicate a projected increase in SSL at several locations along the North European coastline, which is more prominent for RCP8.5 and shows an increasing tendency towards the end of the century for both RCP4.5 and RCP8.5. Projected SSL changes along the European coastal areas south of 50°N show minimal change or even a small decrease, with the exception of RCP8.5 under which a moderate increase is projected towards the end of the century. The present findings indicate that the anticipated increase in extreme total water levels due to relative sea level rise (RSLR), can be further enforced by an increase of the extreme SSL, which can exceed 30 % of the RSLR, especially for the high return periods and pathway RCP8.5. This implies that the combined effect could increase even further anticipated impacts of climate change for certain European areas and highlights the necessity for timely coastal adaptation and protection measures. The dataset is publicly available under this link: http://data.jrc.ec.europa.eu/collection/LISCOAST .

Highlights

The coastal zone is an area of high interest, characterized by increased population density, hosting important commercial activities and constituting habitats of high socioeconomic value (Costanza 1999)
The present findings indicate that the anticipated increase in extreme total water levels due to relative sea level rise (RSLR), can be further enforced by an increase of the extreme storm surge levels (SSL), which can exceed 30 % of the RSLR, especially for the high return periods and pathway RCP8.5
Sea level rise (SLR) in view of climate change poses a serious threat to coastal areas and as a consequence, much research effort has focused on this aspect of coastal hazard (Church and White 2011; Hinkel et al 2014; Hogarth 2014; Hoggart et al 2014; Jevrejeva et al 2014; Losada et al 2013; Tol 2009)

Summary

Introduction

The coastal zone is an area of high interest, characterized by increased population density, hosting important commercial activities and constituting habitats of high socioeconomic value (Costanza 1999). Some studies report an increased intensity and frequency of extreme water levels along several coastal regions in the world (Izaguirre et al 2013; Ullmann and Monbaliu 2010; Wang et al 2014; Weisse et al 2014). The majority of the observed changes are related to changes in mean sea level (Menéndez and Woodworth 2010), while there is a lack of significant trends in storminess (Dangendorf et al 2014a; Woodworth and Blackman 2002). The latter is in agreement to the conclusions of Ferreira et al (2009), who found no statistically significant increasing

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