Comparison of Recent European Climate Trends and Extremes with RegCM3 Future Projections

1. Comparison of Recent European Climate Trends and Extremes with RegCM3 Future Projections Jeremy Pal Abdus Salam International Centre for Theoretical Physics Trieste, Italy Contributors: Xunqiang Bi, Elfatih Eltahir, Raquel Francisco, Xuejie Gao, Filippo Giorgi

2. Premises/Objectives of the study • Climate variability and extremes are of fundamental importance for an assessment of the impacts of climate change. • Because of their relatively high spatial and temporal resolution Regional Climate Models (RCMs) can be especially useful in the study of climate variability and extremes. • Carry out climate change simulations over the European region for different emission scenarios using an RCM driven by boundary conditions from time-slice GCM simulations

3. PART I: Regional Climate Modeling • Brief Overview • PART II: Reference Simulation • Mean Climate • PART III: A2 & B2 Scenario Simulations • Mean • Interannual Variability • Extreme Events

4. PART I:Regional Climate Modeling Brief Overview

5. GCM Global Climate Model (GCM) • RCM Nesting • GCM forces RCM at the lateral boundaries and the sea surface.

6. Added Value of using a Regional Climate Model for Climate Change Studies. • Increased resolution compared to the driving GCM. • Fine scale forcing (e.g. topography, landuse, coastlines, lakes, aerosol sources). • Mesoscale circulations (e.g. North American Monsoon System). • Improved representation of physical processes. • Clouds and precipitation, biosphere, boundary layer, radiation, etc. • Increased confidence for impacts studies. • Can include additional processes not present in the driving GCM. • Landuse changes, aerosol effects, lake desiccation, etc.

7. Dynamics: MM5 Hydrostatic (Grell et al 1994) Non-hydrostatic (in the works) Radiation: CCM3 (Kiehl 1996) Large-Scale Clouds & Precipitation: SUBEX (Pal et al 2000) Cumulus convection: Grell (1993); AS74 & FC80 closure Anthes-Kuo (1977) Betts-Miller (1993) Emanuel (1991) Boundary Layer: Holtslag (1990) Tracers/Aerosols: Qian et al (2001); Solmon Land Surface: BATS (Dickinson et al 1993) SUB-BATS (Giorgi et al 2003) CLM0 (Dai et al 2003) Ocean Fluxes Zeng et al (1998) BATS (Dickinson et al. 1986) Computations Parallel Code (Yeh & Gao) User friendly Multiple platforms • Dynamics: MM5 Hydrostatic (Grell et al 1994) Non-hydrostatic (in the works) • Radiation: CCM3 (Kiehl 1996) • Large-Scale Clouds & Precipitation: SUBEX (Pal et al 2000) • Cumulus convection: Grell (1993); AS74 & FC80 closure Anthes-Kuo (1977) Betts-Miller (1993) Emanuel (1991) • Boundary Layer: Holtslag (1990) • Tracers/Aerosols: Qian et al (2001); Solmon • Land Surface: BATS (Dickinson et al 1993) SUB-BATS (Giorgi et al 2003) CLM0 (Dai et al 2003) • Ocean Fluxes Zeng et al (1998) BATS (Dickinson et al. 1986) • Computations Parallel Code (Yeh & Gao) User friendly Multiple platforms Summary of RegCM3 Core (Giorgi et al 1993ab, Pal et al 2005ab)

8. Ancient Nilometer (Mississippimeter) Date back 1800 B.C. This one calibrated in subjective terms by Pliny the Elder (Dooge 1988) Disaster Abundance Security Happiness Suffering Hunger 1993 Midwest Summer Flood • Record high rainfall (>200 year event) • Thousands homeless • 48 deaths • $15-20 billion in Damage USHCN Observations 1993 1988 RegCM3

9. Ancient Nilometer (Mississippimeter) Date back 1800 B.C. This one calibrated in subjective terms by Pliny the Elder (Dooge 1988) Disaster Abundance Security Happiness Suffering Hunger RegCM 1988 Great North American Drought • Driest/warmest since 1936 • ~10,000 deaths • $30 billion in Agricultural Damage CRU Observations 1993 1988

10. Precipitation over East Asia: CRU Observations RegCM3 September 1994 thru August 1995

11. Scenario Simulations Design of Numerical Experiments

12. Cascade of Uncertainties in Climate Change Prediction Socio-Economic Assumptions Emissions Scenarios Concentration Calculations Biogeochemical/Chemistry Models Interactions and Feedbacks Land Use Change Policy Responses: Adaptation and Mitigation Global Climate Change Simulation AOGCMs, Radiative Forcing Natural Forcings Regional Climate Change Simulations Regionalization Techniques Impacts Impact Models

13. Model Configuration • ICTP RegCM3 • 50 km • 121 x 100 x 14 • HadAMH SST, GHG & Sulfate • Aerosol effects (direct & indirect) • Simulations • Reference run • 1961-1990 • A2 & B2 Scenario runs • 2071-2100 • Mediterranean Focused

14. GLCC Vegetation HadAMH3 Initial and Boundary Conditions HadAMH3 Aerosols Rotated Mercator Projection USGS Topography Regional Climate Model Schematic Hadley & OI Sea Surface Temperatures

15. SCENARIOS CO2 Concentrations (ppm) CO2 Emissions (Gt C) A2 A2 B2 B2

16. PART II:Reference Simulation Comparison to Observations Giorgi, Bi, Pal, Clim. Dynamics 2004a

17. Winter Means Reference Period

18. Surface Air Temperature: Reference Simulation Winter Observations Winter RegCM3

19. Precipitation: Reference Simulation Winter Observations Winter RegCM3

20. Summer Means Reference Period

21. Surface Air Temperature: Reference Simulation Summer Observations Summer RegCM3

22. Precipitation: Reference Simulation Summer Observations Summer RegCM3

23. PART III:A2 & B2 Scenario Simulations Comparison to the Reference Simulation Giorgi, Bi, Pal, Clim. Dynamics 2004b Pal, Giorgi, Bi, GRL 2004

24. Winter Means Scenarios

25. Temperature Change: Future-Reference WARM B2-REF Winter RegCM3 A2-REF Winter RegCM3 HOT WARM

26. Precipitation Change: Future-Reference WET B2-REF Winter RegCM3 DRY WET WET A2-REF Winter RegCM3 DRY

27. Sea Level Pressure Change: Future-Reference L H H B2-REF Winter RegCM3 L H A2-REF Winter RegCM3

28. Winter Sea Level Pressure Change: B2 & A2 Scenarios DJF HadAMH: B2 DJF RegCM: B2 L L H H H H DJF HadAMH: A2 DJF RegCM: A2 L L H H

29. Summer Means Scenarios

30. Temperature Change: Future-Reference B2-REF Summer RegCM3 WARM A2-REF Summer RegCM3 WARM HOT

31. Precipitation Change: Future-Reference WET B2-REF Summer RegCM3 DRY A2-REF Summer RegCM3 WET DRY

32. Sea Level Pressure Change: Future-Reference L H B2-REF Summer RegCM3 L H A2-REF Summer RegCM3

33. Winter Sea Level Pressure Change: B2 & A2 Scenarios JJA HadAMH: B2 JJA RegCM: B2 L L H H JJA HadAMH: A2 JJA RegCM: A2 L L H H

34. Interannual Variability Scenarios

35. Map of Domain & Topography SEM

36. DJF, A2 JJA, A2 DJF, B2 JJA, B2 Surface Air Temperature: Interannual Variability Changes RegCM3: Future-REF SEM Sub-region Averages

37. DJF, A2 JJA, A2 DJF, B2 JJA, B2 Precipitation: Interannual Variability Changes RegCM3: Future-REF SEM Sub-region Averages

38. Extremes How do recent climatic changes compare to scenarios? Pal, Giorgi, Bi, GRL 2004

39. Recent European Extreme Summers • The western European summer drought of 2003 is considered one of the severest on record. • 20,000 heat related casualties in Western Europe. • Worst harvest since World War II. • In contrast, during 2002, many European countries experienced one of their wettest summers on record. • Weather systems brought widespread heavy rainfall to central Europe, causing severe flooding along all the major rivers. • The Elbe River reached its highest level in over 500 years of record • Both of these contrasting events resulted in severe damages and losses. • This study addresses whether these seemingly opposites in extremes are consistent the current climate change projections.

40. B2-Reference (2071-2100) minus (1961-1990) ( meters) Changes in Summer500 hPa Geopotential Heights NCEP Reanalysis (1976-2000) minus (1951-1975) ( meters)

41. Changes in Summer Temperature B2-Reference (2071-2100) minus (1961-1990) CRU Observations (1976-2000) minus (1951-1975) (C) (C)

42. Changes in Summer Precipitation B2-Reference (2071-2100) minus (1961-1990) CRU Observations (1976-2000) minus (1951-1975) (% change) (% change)

43. Changes in Summer Temperature:B2-Reference Interannual Variability (2071-2100) minus (1961-1990) Mean Surface (2071-2100) minus (1961-1990) (C) (C)

44. Changes in Summer Extremes:B2-Reference Max 5-Day Precipitation (2071-2100) minus (1961-1990) Dry Spell Length (2071-2100) minus (1961-1990) ( Days) (% change)

45. REF Drier Summers ref B2 B2 More Floods More Droughts B2 ref Precipitation Distribution(Hypothetical)

46. Summary & Conclusions • The RegCM3 reproduces the main features of observed temperature and precipitation. • A general consistency of change patterns is found between the A2 and B2 scenarios. • Warming: • 2-7 oC in the A2 scenario is found over land areas. • The B2 scenario is 1-2 oC lower. • Precipitation: • Increases in Northern Europe during summer and winter • Increases in the Mediterranean in DJF and decreases in JJA. • Interannual variability: • Mostly increases in JJA • Little change in DJF. • Extremes: • Increases flooding in Northern Europe • Increased summer flood and drought in the Mediterranean. • Projected changes of mean summer European climate are broadly consistent with the observed changes.

47. 谢谢