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

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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
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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

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

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PART IRegional Climate Modeling

• Brief Overview

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(No Transcript)
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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.

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Summary of RegCM3 Core

• 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

(Giorgi et al 1993ab, Pal et al 2005ab)
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1993 Midwest Summer Flood

• Record high rainfall (gt200 year event)
• Thousands homeless
• 48 deaths
• 15-20 billion in Damage

USHCN Observations
1993
1988
RegCM3
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1988 Great North American Drought

• Driest/warmest since 1936
• 10,000 deaths
• 30 billion in Agricultural Damage

CRU Observations
1993
1988
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Precipitation over East Asia
CRU Observations
RegCM3
September 1994 thru August 1995
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Scenario Simulations

• Design of Numerical Experiments

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Cascade of Uncertainties in Climate Change
Prediction
Socio-Economic Assumptions
Emissions Scenarios
Concentration Calculations Biogeochemical/Chemistr
y 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
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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

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Regional Climate Model Schematic
Hadley OI Sea Surface Temperatures
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SCENARIOS
CO2 Emissions (Gt C)
CO2 Concentrations (ppm)
A2
A2
B2
B2
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PART IIReference Simulation

• Comparison to Observations
• Giorgi, Bi, Pal, Clim. Dynamics 2004a

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Winter Means

• Reference Period

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Surface Air Temperature Reference Simulation
Winter Observations
Winter RegCM3
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Precipitation Reference Simulation
Winter Observations
Winter RegCM3
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Summer Means

• Reference Period

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Surface Air Temperature Reference Simulation
Summer Observations
Summer RegCM3
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Precipitation Reference Simulation
Summer Observations
Summer RegCM3
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PART IIIA2 B2 Scenario Simulations

• Comparison to the Reference Simulation
• Giorgi, Bi, Pal, Clim. Dynamics 2004b
• Pal, Giorgi, Bi, GRL 2004

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Winter Means

• Scenarios

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Temperature Change Future-Reference
WARM
B2-REF Winter RegCM3
A2-REF Winter RegCM3
HOT
WARM
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Precipitation Change Future-Reference
WET
B2-REF Winter RegCM3
DRY
WET
WET
A2-REF Winter RegCM3
DRY
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Sea Level Pressure Change Future-Reference
L
H
H
B2-REF Winter RegCM3
L
H
A2-REF Winter RegCM3
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Winter Sea Level Pressure Change B2 A2
Scenarios
DJF HadAMH B2
DJF RegCM B2
L
L
H
H
H
H
DJF RegCM A2
DJF HadAMH A2
L
L
H
H
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Summer Means

• Scenarios

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Temperature Change Future-Reference
B2-REF Summer RegCM3
WARM
A2-REF Summer RegCM3
WARM
HOT
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Precipitation Change Future-Reference
WET
B2-REF Summer RegCM3
DRY
A2-REF Summer RegCM3
WET
DRY
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Sea Level Pressure Change Future-Reference
L
H
B2-REF Summer RegCM3
H
L
A2-REF Summer RegCM3
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Winter Sea Level Pressure Change B2 A2
Scenarios
JJA HadAMH B2
JJA RegCM B2
L
L
H
H
JJA RegCM A2
JJA HadAMH A2
L
L
H
H
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Interannual Variability

• Scenarios

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Map of Domain Topography
SEM
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Surface Air Temperature Interannual Variability
Changes
RegCM3 Future-REF
SEM
Sub-region Averages
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Precipitation Interannual Variability Changes
RegCM3 Future-REF
SEM
Sub-region Averages
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Extremes

• How do recent climatic changes compare to
  scenarios?
• Pal, Giorgi, Bi, GRL 2004

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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.

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Changes in Summer500 hPa Geopotential Heights
NCEP Reanalysis (1976-2000) minus (1951-1975)
(? meters)
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Changes in Summer Temperature
B2-Reference (2071-2100) minus (1961-1990)
CRU Observations (1976-2000) minus (1951-1975)
(C)
(C)
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Changes in Summer Precipitation
B2-Reference (2071-2100) minus (1961-1990)
CRU Observations (1976-2000) minus (1951-1975)
( change)
( change)
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Changes in Summer TemperatureB2-Reference
Interannual Variability (2071-2100) minus
(1961-1990)
Mean Surface (2071-2100) minus (1961-1990)
(C)
(C)
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Changes in Summer ExtremesB2-Reference
Max 5-Day Precipitation (2071-2100) minus
(1961-1990)
Dry Spell Length (2071-2100) minus (1961-1990)
( change)
(? Days)
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Precipitation Distribution(Hypothetical)
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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.

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