Presentation on theme: "Jeremy Pal Abdus Salam International Centre for Theoretical Physics"— Presentation transcript:
1Comparison of Recent European Climate Trends and Extremes with RegCM3 Future Projections Jeremy PalAbdus Salam International Centre for Theoretical PhysicsTrieste, ItalyContributors: Xunqiang Bi, Elfatih Eltahir,Raquel Francisco, Xuejie Gao, Filippo Giorgi
2Premises/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
5Global Climate Model (GCM) RCM NestingGCM forces RCM at the lateral boundaries and the sea surface.Global Climate Model (GCM)
6Added 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.
7Summary 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 closureAnthes-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 closureAnthes-Kuo (1977)Betts-Miller (1993)Emanuel (1991)Boundary Layer:Holtslag (1990)Tracers/Aerosols:Qian et al (2001); SolmonLand Surface:BATS (Dickinson et al 1993)SUB-BATS (Giorgi et al 2003)CLM0 (Dai et al 2003)Ocean FluxesZeng et al (1998)BATS (Dickinson et al. 1986)ComputationsParallel Code (Yeh & Gao)User friendlyMultiple platformsTracers/Aerosols:Qian et al (2001); SolmonLand Surface:BATS (Dickinson et al 1993)SUB-BATS (Giorgi et al 2003)CLM0 (Dai et al 2003)Ocean FluxesZeng et al (1998)BATS (Dickinson et al. 1986)ComputationsParallel Code (Yeh & Gao)User friendlyMultiple platforms(Giorgi et al 1993ab, Pal et al 2005ab)
81993 Midwest Summer Flood Record high rainfall (>200 year event) Thousands homeless48 deaths$15-20 billion in DamageUSHCN ObservationsAncient Nilometer(Mississippimeter)Date back 1800 B.C.This one calibrated insubjective terms byPliny the Elder(Dooge 1988)DisasterAbundanceSecurityHappinessSufferingHunger19931988RegCM3
91988 Great North American Drought Driest/warmest since 1936~10,000 deaths$30 billion in Agricultural DamageCRU ObservationsRegCMAncient Nilometer(Mississippimeter)Date back 1800 B.C.This one calibrated insubjective terms byPliny the Elder(Dooge 1988)DisasterAbundanceSecurityHappinessSufferingHunger19931988
10Precipitation over East Asia: CRU ObservationsRegCM3September 1994 thru August 1995
11Design of Numerical Experiments Scenario SimulationsDesign of Numerical Experiments
12Cascade of Uncertainties in Climate Change Prediction Socio-Economic AssumptionsEmissions ScenariosConcentration CalculationsBiogeochemical/Chemistry ModelsInteractions and FeedbacksLand Use ChangePolicy Responses: Adaptation and MitigationGlobal Climate Change SimulationAOGCMs, Radiative ForcingBiggest uncertainties are in the Emissions scenarios and the climate projections (I.e., climate model sensitivity).NaturalForcingsRegional Climate Change SimulationsRegionalization TechniquesImpactsImpact Models
14Regional Climate Model Schematic GLCCVegetationHadley & OISea SurfaceTemperaturesHadAMH3 Initial and Boundary ConditionsHadAMH3 AerosolsRotatedMercatorProjectionUSGSTopography
15SCENARIOS 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.B2B2
38How do recent climatic changes compare to scenarios? ExtremesHow do recent climatic changes compare to scenarios?Pal, Giorgi, Bi, GRL 2004
39Recent 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 recordBoth 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.
40Changes in Summer 500 hPa Geopotential Heights NCEP Reanalysis( ) minus ( )( meters)B2-Reference( ) minus ( )( meters)
41Changes in Summer Temperature CRU Observations( ) minus ( )B2-Reference( ) minus ( )(C)(C)
42Changes in Summer Precipitation CRU Observations( ) minus ( )B2-Reference( ) minus ( )(% change)(% change)
43Changes in Summer Temperature: B2-Reference Mean Surface( ) minus ( )Interannual Variability( ) minus ( )(C)(C)
44Changes in Summer Extremes: B2-Reference Dry Spell Length( ) minus ( )Max 5-Day Precipitation( ) minus ( )( Days)(% change)
45Precipitation Distribution (Hypothetical) REFrefrefB2B2B2MoreDroughtsFloodsDrierSummers
46Summary & ConclusionsThe 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 winterIncreases in the Mediterranean in DJF and decreases in JJA.Interannual variability:Mostly increases in JJALittle change in DJF.Extremes:Increases flooding in Northern EuropeIncreased summer flood and drought in the Mediterranean.Projected changes of mean summer European climate are broadly consistent with the observed changes.