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 PART II: Reference Simulation
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. Global Climate Model (GCM)
RCM Nesting
GCM forces RCM at the lateral boundaries and the sea surface.
Global Climate Model (GCM)

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. Summary of RegCM3 Core Dynamics: Radiation:
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)
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
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
(Giorgi et al 1993ab, Pal et al 2005ab)

8. 1993 Midwest Summer Flood Record high rainfall (>200 year event)
Thousands homeless
48 deaths
$15-20 billion in Damage
USHCN Observations
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
1988
RegCM3

9. 1988 Great North American Drought
Driest/warmest since 1936
~10,000 deaths
$30 billion in Agricultural Damage
CRU Observations
RegCM
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
1988

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

11. Design of Numerical Experiments
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
Biggest uncertainties are in the Emissions scenarios and the climate projections (I.e., climate model sensitivity).
Natural
Forcings
Regional Climate Change Simulations
Regionalization Techniques
Impacts
Impact Models

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

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

15. SCENARIOS CO2 Emissions (Gt C) CO2 Concentrations (ppm) A2 A2 B2 B2
These figures are not cumulative, but show emissions/year.
Note big difference in the sulphate emissions from the IS92a scenario of SAR. IN SRES scenarios for all scenarios sulfates start declining by about 2040 or before. 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
A2-REF Winter
RegCM3
WET
DRY

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

34. Interannual Variability
Scenarios

35. Map of Domain & Topography
SEM

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

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

38. How do recent climatic changes compare to scenarios?
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. Changes in Summer 500 hPa Geopotential Heights
NCEP Reanalysis
( ) minus ( )
( meters)
B2-Reference
( ) minus ( )
( meters)

41. Changes in Summer Temperature
CRU Observations
( ) minus ( )
B2-Reference
( ) minus ( )
(C)
(C)

42. Changes in Summer Precipitation
CRU Observations
( ) minus ( )
B2-Reference
( ) minus ( )
(% change)
(% change)

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

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

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

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