IMPACT OF POSSIBLE FUTURE CLIMATE ON COASTAL WINDS,

STORM SURGES AND WAVE CONDITIONS IN THE NORTH SEA

Hans VON STORCH, Arnt PFIZENMAYER, Ralf WEISSE, Katja WOTH, Institute for Coastal Research,

GKSS Research Center, Geesthacht, Germany

PACON, Kaoshiung, 2 December 2003 (OST-1: Climate Change)

Series of EU projects

• WASA (1995-97)

• STOWASUS (1998-2001)

• PRUDENCE (2001-2003)

Changing Scenarios

• Different emission scenarios, IS92a, SRES

• Different models, ECHAM, HADCM etc.

• Different regionalization: global T106 time slices, empirical downscaling, regional climate models; impact models (waves, storm surges)

• SIMILAR RESULTS

WASA: Mögliche Änderung der Windgeschwindigkeit der größten Stürme bei CO2 Verdopplung

STOWASUS: Ein ähnliches Szenario

WA

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WASA results: 5 years of T106 „2 x CO2“ time slice experiment

North Sea wind: increase of up to 0.5 m/s (10%ile)

Kauker

and L

angenberg

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WASA results: 5 years of T106 „2 x CO2“ time slice experiment

Mean water level: +10 cm

Storm related sea level: + 5 cm

Langenberg

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99

WASA results: 5 years of T106 „2 x CO2“ time slice experiment

Zukünftige Szenarien

WASA: Mögliche Änderung der Höhen der größten Wellen bei CO2 Verdopplung

CDV-2075: Mögliche Änderung des Überspülens von Deichen bei CO2 Zunahme

Günth

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WASA results: 5 years of T106 „2 x CO2“ time slice experiment

North Sea waveheight: increase of up to 0.5 m (10%ile)

Anders

en

et

al.,

200

1

STOWASUS results: 30 years of T106 „2 x CO2“ time slice experiment

North Sea wind: increase of up to 2 m/s (0.1%ile)

STOWASUS results: 30 years of T106 „2 x CO2“ time slice experiment

Flath

er

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iliam

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00

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North Sea elevation: increase of up to 40 cm (estimated 50 yr return values)

Kaas

et

al., 20

01North Sea

elevation: increase of up to 20 cm (estimated 50 yr return values)

RIKZ

STOWASUS results: 30 years of T106 „2 x CO2“ time slice experiment

Kaas

et

al., 20

01

North Sea waveheight: increase of up to 0.5 m (0.1%ile)

Mean and 99 percentile of wind speed obtained from CTL run and A2Contour lines - mean percentiles of CTL

Colour: Changes in wind speed in the scenario relative to the control run.

Projections for the future / 10 m wind speed Projections for the future / 10 m wind speed difference in percentiles (A2 - CTL)difference in percentiles (A2 - CTL)

PRUDENCE results: RCM downscaling of HADCM3 A2 scenario, 2070-2100

HIRHAMRCA

Projections for the future / surge Projections for the future / surge meteorological forcing: HIRHAM / RCAmeteorological forcing: HIRHAM / RCA

Differences in inter-annual percentiles of surge / A2 - CTL: HIRHAM

Differences in inter-annual percentiles of surge / A2 - CTL: RCA

Katj

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oth

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PRUDENCE results: RCM downscaling of HADCM3 A2 scenario, 2070-2100

Projections for the future :Projections for the future :return valuesreturn values

50 year return value / CTL and A2 and 90 % confidence limits based on 1000 Monte Carlo simulations:

HIR

HA

MR

CA

Cont. North Sea coastEast coast of UK

Katj

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oth

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PRUDENCE results: RCM downscaling of HADCM3 A2 scenario, 2070-2100

The scenarios indicate uniformly for the North Sea:

• A slight increase of higher wind percentiles of up to 0.5-2 m/s.

• A slight increase of storm surge levels, of up to 20-40 cm.

• A slight increase in significant wave height of up to 0.5 m.

Conclusions