Presentation on theme: "Climate change and North Sea storm surge extremes - an ensemble study (PRUDENCE) Katja Woth & Hans von Storch Institute for Coastal Research GKSS Research."— Presentation transcript:
Climate change and North Sea storm surge extremes - an ensemble study (PRUDENCE) Katja Woth & Hans von Storch Institute for Coastal Research GKSS Research Center Geesthacht, Germany
Institute for Coastal Research GKSS, Germany Assessing ongoing change of coastal climate. Deriving scenarios of plausible, possible futures of coastal climates. Special emphasis on wind-related aspects, i.e., wind force, storm surges and ocean waves. Special emphasis on North Sea and Baltic Sea. Participant in HIPOCAS, PRUDENCE and ENSEMBLES.
NCEP Globale Reanalysen ( 210 km x 210 km ) WAM sig. Wellenhöhe und Richtung UTC BAW - TELEMAC 2D Wasserstand und barotrope Strömung UTC Auflösung zwischen etwa 100 m und 5km Auflösung etwa 5 x 5 km Auflösung etwa 50 x 50 km REMO Windgeschwindigkeit und Richtung UTC HIPOCAS: Für Rekonstruktionen verwendete Modellkette Gebiet hier: Nordsee und östlicher Nordatlantik
Climate risk assessments done with these models Reconstruction of past and ongoing state and change PCPnP futures (PCPnP = plausible, consistent, possible but not necessarily probable = scenarios)
Not assimilated into NCEP (Ionic Sea) Comparison of wind speed statistics with in-situ data: RCM is skillful in describing marine wind statistics
External Forcing – Future Scenarios
EU-Project PRUDENCE (Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects) Impact scenarios today scenario GCM today scenario RCMs scale globallocal Impactmodel Storm Surge Model for the North Sea: - TRIM 3D Regional Climate Models: - CLM - REMO - HIRHAM - RCAO Global Climate Model (HadAM3) IPCC A2 SRES Scenario ( / )
RCAOHIRHAM CLM REMO5 A2 - CTL: changes in 99 % - iles of wind speed (6 hourly, DJF): west wind sector selected (247.5 to deg)
Projections for the future / surge meteorological forcing: HIRHAM / RCA Differences in inter-annual percentiles of surge / A2 - CTL: HIRHAM Differences in inter-annual percentiles of surge / A2 - CTL: RCA
Mean change of winter 95%ile surge levels Near coastal model cells
SREs emission scenarios: Impact on global sea level IPCC, 2001 According to scenario A2 and the specific set of GCM / RCMs, water level may rise in extreme situations by as much as 40 cm + 30 cm = 70 cm along the German North Sea coast.
Conclusions Dynamical models have been demonstrated to be a useful tool to describe the statistics, and changes thereof, of wind-related phenomena in coastal seas – wind force, storm surge, coastal currents and ocean waves. An ensemble of regionalizations, derived from one global A2 scenario, results in rather similar changes of regional wind over the North sea and the associated change of surge levels. Along the German North Sea coast, water levels may rise by up to 70 cm - of which 40 cm are due to mean sea level rise and 30 cm to different storm patterns.