1. Cambio Climático y eventos extremos: un enfoque dinámico Grupo de Física del Clima E.Sánchez Gómez, A. Ruiz de Elvira, W. Cabos Narváez, F.J. Alvarez García y M.J. Ortiz Beviá Universidad de Alcalá

2. Scheme of the talk General view: Current researching activities of the group: -Climatic Variability -Empirical Predictability -Climatic Change Climate Change and climate extreme events We focus on: Colaboration with:

3. Main topics of GFSC: Climate variability - Development of a regional version of a GCM (OPYC) for the Atlantic Ocean. - Analysis of the interannual variability of the Tropical Atlantic, North Atlantic and Mediterranean Sea. -Scale interactions and physical mechanisms of the interannual variability: analysis of a coupled ocean- atmosphere GCM simulations with statistical tools

4. Main topics of GFSC: Empirical Predictability - Real retroactive empirical forecasts issued for the Tropical Oceans (Nino3 index, GG index, NTA index). -Empirical forecast of the North Atlantic air temperature anomalies (also Iberian Peninsula) and of the NAO index.

5. Empirical predictability in the North Atlantic Great Anomaly of Salinity (Dickson et al. 1998) The empirical forecasts are able to detect climatic changes: we observe an evident decrease of predictability in the 80s, caused by significant changes occurred at the end of the 70s: NAO index and the GSA (SanchezGomez et al. 2001). First EOF of sea ice field in the North Atlantic (66%) Changes in the NAO phase

6. Main Topics of GFSC: Climatic Change - Colaboration with the Departamento de Puertos del Estado (WASA group). Detection the swell changes in the north coast of Spain, with he help of the swell simulations from the WAM model. - Characterization of climatic changes in the Spain (Meseta Sur). Climate extreme events! (indices proposed by WMO-CCI/CLIVAR)

7. Climate change and extreme climate events Weather regimes approach - Four classical weather regimes in the North Atlantic basin in winter and in summer (Vautard 1990). - They have been identified by a cluster technique (k-means, Michelangeli et al. 1991) from 500 mb field (ERA40). We can find the links between the weather regimes and some extreme climate events over a region (Spain). 1. 2. The simulations from ARPEGE-Climat model (control and scenario) allow us for determining the possible changes in the percentage of occurrence of a weather regime. Then we can somehow ‘predict’ the changes in frequency of an extreme climate event. 3.

8. Climate change and extreme climate events Weather regimes in ERA40 (winter) Greenland Anticyclone(GA) 7j 16%Atlantic Ridge (AR) 6j 16% Blocking (BL) 6j 17%Zonal (ZO) 8j 22%

9. Climate change and extreme climate events Weather regimes in ERA40 (summer) Greenland Anticyclone(GA) 7j 11%Atlantic Ridge(AR) 6j 15% Blocking (BL) 6j 14% Zonal (ZO) 7j 12%

10. Climate change and extreme climate events - Extreme events are identified by a threshold value (5%, 95% quantiles). - Variables: Tmax, Tmin, Precipitation, Storm Tracks Extreme climate events Threshold value 5%PX%PX% Change of probability: C = (Px/5)-1) *100 Px=10; C=100% Px=15; C=200% Px=0; C=-100% !!

11. Climate change and extreme climate events Extreme climate events Some applications already carried out in France (SQR data) ZonalBlocking Winter precipitationWinter Tmin Summer Tmax Next: 53 meteorological stations Tmin, Tmax and precipitation in Spain (Meseta Sur) provided by the INM. Sánc hezGómez E., Gosetlogon G de, L. Terray and A. Joly (2005) ‘Weather regimes links with Temperature and precipitation extremes’, Climate Dynamics, (submitted).

12. Climate change and extreme climate events Extreme climate events : Storms (With the help of storm tracking carried out by A. Joly and F. Ayrault) Atlantic RidgeGreenland Anticyclone BlockingZonal

13. Climate change and extreme climate events Weather regimes in ARPEGE-Climat Stretched grid, Variable Resolution ~ 60 Km over France and Spain ~ 600 Km over the Southern Pacific (Déqué et al. 1998) Data: -3 simulations of control (1960-1999) -3 simulations of scenario A2 from IPCC (2070-2099)

14. Climate change and extreme climate events Weather regimes in ARPEGE-Climat (winter) Climat PrésentClimat FuturERA40 GA AR BL ZO 22% 24% 30% 28% 24% 21% 27% 8% 18% 35% 39% ± 6% ± 2% ± 3%

15. Climate change and extreme climate events Weather regimes in ARPEGE-Climat (winter) Climat Présent ERA40 GA AR BL ZO 22% 24% 30% 28% 24% 21% 27% 8% 18% 35% 39%

16. Climate change and extreme climate events Weather regimes in ARPEGE-Climat (summer) Climat Présent ERA40 GA AR BL ZO 29% 22% 24% 25% 27% 26% 21% 26% 5% 2% 70% 23% ± 1% ± 4% ± 2%

17. Climate change and extreme climate events Weather regimes in ARPEGE-Climat (summer) Climat PrésentClimat FuturERA40 GA AR BL ZO 29% 22% 24% 25% 27% 26% 21% 26% 5% 2% 70% 23% !

18. Conclusions: Main topics of GFSC Climatic Variability (Atlantic Ocean, ENSO) Empirical Predictability Climatic Change Impact of climatic change in the frequency and intensity of the climate extreme events (Meseta Sur)