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Mediterranean Sea Level Rise Scenarios from CIRCE

S. Dobricic on behalf of the CIRCE project team: M. Adani, S. Gualdi, S. Somot,

W. May, S. Castellari, M. Déqué, V. Artale, A, Bellucci, J. S. Breitgand, A. Carillo,

R. Cornes, A. Dell’Aquila, C. Dubois, D. Efthymiadis, A. Elizalde, L. Gimeno, C. M.

Goodess, A. Harzallah, S.O. Krichak, F.G. Kuglitsch, G.C. Leckebusch, B.

L’Heveder, L. Li, P. Lionello, J. Luterbacher, A. Mariotti, R. Nieto, K. M. Nissen, P.

Oddo, P. Ruti, A. Sanna, G. Sannino, E. Scoccimarro, M. V. Struglia, A. Toreti, U.

Ulbrich, E. Xoplaki, G. Coppini, N. Pinardi, A. Bonaduce, G. Larnicol, I. Poujol, M.

Ablain

• Main principles of the multimodel forecasting in CIRCE

• Ongoing changes of the sea level in the Mediterranean

• Multimodel forecasts of main parameters including sea level

Outline:

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• Provide a basic assessment of the climate change signal

• A multi-model approach

• Collaborative and coordinated assessment

• Evaluate the ability of models to make long term forecasts

Main principles of CIRCE forecasting

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Coarse resolution models (e.g., ENSEMBLES, PRUDENCE and CMIP3-IPCC AR4, …)

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Orography, Land-Sea mask and Mediterranean Sea bathymetry in a CMIP3 (IPCC-AR4) model with horizontal resolution of ~300 Km

~300 Km

m

1°

m

State of the art before CIRCE

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High-resolution and coupled atmosphere-ocean in the Mediterranean region

CIRCE models

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CIRCE models

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CIRCE simulations

• Spin-up: long integration performed with the observed 1950s (permanent) conditions (radiative forcing)

• Initial conditions: oceanic mean state obtained from Levitus or MedAtlas-II

• Integration 1951-2000: radiative forcing (GHGs and aerosol) prescribed according to observations (CMIP3)

• projection 2001-2050: radiative forcing (GHGs and aerosol) prescribed according to the A1B AR4-SRES (CMIP3)

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Evolution of the T2m

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10*(

°C/d

ecad

e)

T2m trend 2001-2050 JJA

T2m trend 2001-2050 DJF

(mm

/day

)/de

cade

Precip trend 2001-2050 DJF

Precip trend 2001-2050 JJA

T2m and Precipitation projected trends

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Present Sea Level trends

1.8

2.5

1.9

3.6

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Ongoing Sea Level Change: Observations and CIRCE reanalyses

Satellite SLA

observations

StericHeight

Re-analyses

TemperatureHeight

Re-analyses

SalinityHeight

Re-analyses

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Steric component of Sea Level Changeestimated by CIRCE

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Summary of CIRCE forecasts

The CIRCE projections for the 21st century suggest that remarkable changes in the climate of the Mediterranean region might occur already in the next few decades

•The Mediterranean lands will be about 20C warmer

•The SST will be 1-20C warmer.

•The precipitation will decrease (5% -10%)

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Summary of CIRCE forecasts:Ongoing sea level change and future projections

•Satellite observations show that the Mediterranean sea level rise trend is lower than the global. The CIRCE reanalyses suggest that the expansion of water due to the sea temperature rise is suppressed by the contraction due to the rise of the salinity. The total steric height trend is negative and it balances the global sea level rise due to the ice melting. •The CIRCE forecasts indicate that this trend will be inverted already in the next decade and the steric sea level will rise by 15cm in the first half of the 21st century

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Averaged value (± std) over the periods 1961-1990 and 2021-2050 of the outflow, inflow, and net water transport. Observations are from the period 2004-2009 (Soto-Navarro et al. 2010)

OUTFLOW INFLOW NET TRANSPORT

1961-1990

2021-2050

Water transport:Strait of Gibraltar