Transcript Slide 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 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 PART I: Regional Climate Modeling PART II: Reference Simulation Brief Overview Mean Climate PART III: A2 & B2 Scenario Simulations Mean Interannual Variability Extreme Events PART I: Regional Climate Modeling Brief Overview GCM Global ClimateRCM ModelNesting (GCM) GCM forces RCM at the lateral boundaries and the sea surface. Added Value of using a Regional Climate Model for Climate Change Studies. Increased resolution compared to the driving GCM. Improved representation of physical processes. Fine scale forcing (e.g. topography, landuse, coastlines, lakes, aerosol sources). Mesoscale circulations (e.g. North American Monsoon System). 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. Summary of RegCM3 Core Dynamics: Tracers/Aerosols: MM5 Hydrostatic (Grell et al 1994) Qian et al (2001); Solmon Non-hydrostatic (in the works) Land Surface: Radiation: BATS (Dickinson et al 1993) CCM3 (Kiehl 1996) SUB-BATS (Giorgi et al 2003) CLM0 (Dai et al 2003) 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 Ocean Fluxes Zeng et al (1998) BATS (Dickinson et al. 1986) Computations Parallel Code (Yeh & Gao) User friendly Multiple platforms Layer: Holtslag (1990) (Giorgi et al 1993ab, Pal et al 2005ab) 1993 Midwest Summer Flood • Record high rainfall (>200 year event) • Thousands homeless • 48 deaths USHCN Observations • $15-20 billion in Damage 1993 Disaster Abundance Security Happiness Suffering Hunger 1988 Ancient Nilometer (Mississippimeter) Date back 1800 B.C. This one calibrated in subjective terms by Pliny the Elder (Dooge 1988) RegCM3 1988 Great North American Drought • Driest/warmest since 1936 • ~10,000 deaths • $30 billion in Agricultural CRU Observations Damage 1993 Disaster Abundance Security Happiness Suffering Hunger 1988 Ancient Nilometer (Mississippimeter) Date back 1800 B.C. This one calibrated in subjective terms by Pliny the Elder (Dooge 1988) RegCM Precipitation over East Asia: CRU Observations RegCM3 September 1994 thru August 1995 Scenario Simulations Design of Numerical Experiments Socio-Economic Assumptions Emissions Scenarios Concentration Calculations Biogeochemical/Chemistry Models Global Climate Change Simulation AOGCMs, Radiative Forcing Regional Climate Change Simulations Regionalization Techniques Impacts Impact Models Natural Forcings Interactions and Feedbacks Land Use Change Policy Responses: Adaptation and Mitigation Cascade of Uncertainties in Climate Change Prediction 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 Regional Climate Model Schematic GLCC Vegetation Hadley & OI Sea Surface Temperatures HadAMH3 Initial and Boundary Conditions HadAMH3 Aerosols USGS Topography Rotated Mercator Projection SCENARIOS CO2 Concentrations (ppm) CO2 Emissions (Gt C) A2 A2 B2 B2 PART II: Reference Simulation Comparison to Observations Giorgi, Bi, Pal, Clim. Dynamics 2004a Winter Means Reference Period Surface Air Temperature: Reference Simulation Winter Observations Winter RegCM3 Precipitation: Reference Simulation Winter Observations Winter RegCM3 Summer Means Reference Period Surface Air Temperature: Reference Simulation Summer Observations Summer RegCM3 Precipitation: Reference Simulation Summer Observations Summer RegCM3 PART III: A2 & B2 Scenario Simulations Comparison to the Reference Simulation Giorgi, Bi, Pal, Clim. Dynamics 2004b Pal, Giorgi, Bi, GRL 2004 Winter Means Scenarios Temperature Change: Future-Reference WARM B2-REF Winter RegCM3 A2-REF Winter RegCM3 HOT WARM Precipitation Change: Future-Reference WET B2-REF Winter RegCM3 A2-REF Winter RegCM3 DRY WET WET DRY Sea Level Pressure Change: Future-Reference L B2-REF Winter RegCM3 A2-REF Winter RegCM3 H H L H Winter Sea Level Pressure Change: B2 & A2 Scenarios DJF HadAMH: B2 DJF RegCM: B2 L L H H H H DJF HadAMH: A2 L DJF RegCM: A2 H L H Summer Means Scenarios Temperature Change: Future-Reference B2-REF Summer RegCM3 A2-REF Summer RegCM3 WARM WARM HOT Precipitation Change: Future-Reference WET B2-REF Summer RegCM3 A2-REF Summer RegCM3 DRY WET DRY Sea Level Pressure Change: Future-Reference L H B2-REF Summer RegCM3 A2-REF Summer RegCM3 H L Winter Sea Level Pressure Change: B2 & A2 Scenarios JJA HadAMH: B2 JJA RegCM: B2 L L H H JJA HadAMH: A2 H JJA RegCM: A2 L H L Interannual Variability Scenarios Map of Domain & Topography SEM Surface Air Temperature: Interannual Variability Changes RegCM3: Future-REF DJF, A2 DJF, B2 JJA, A2 JJA, B2 SEM Sub-region Averages Precipitation: Interannual Variability Changes RegCM3: Future-REF DJF, A2 DJF, B2 JJA, A2 JJA, B2 SEM Sub-region Averages Extremes How do recent climatic changes compare to scenarios? Pal, Giorgi, Bi, GRL 2004 Recent European Extreme Summers The western European summer drought of 2003 is considered one of the severest on record. In contrast, during 2002, many European countries experienced one of their wettest summers on record. 20,000 heat related casualties in Western Europe. Worst harvest since World War II. 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. Changes in Summer 500 hPa Geopotential Heights NCEP Reanalysis B2-Reference (1976-2000) minus (1951-1975) (2071-2100) minus (1961-1990) ( meters) ( meters) Changes in Summer Temperature CRU Observations B2-Reference (1976-2000) minus (1951-1975) (2071-2100) minus (1961-1990) (C) (C) Changes in Summer Precipitation CRU Observations B2-Reference (1976-2000) minus (1951-1975) (2071-2100) minus (1961-1990) (% change) (% change) Changes in Summer Temperature: B2-Reference Mean Surface Interannual Variability (2071-2100) minus (1961-1990) (2071-2100) minus (1961-1990) (C) (C) Changes in Summer Extremes: B2-Reference Dry Spell Length Max 5-Day Precipitation (2071-2100) minus (1961-1990) (2071-2100) minus (1961-1990) ( Days) (% change) Precipitation Distribution (Hypothetical) REF Drier Summers ref B2 More Droughts B2 More Floods B2 ref 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: Precipitation: Mostly increases in JJA Little change in DJF. Extremes: Increases in Northern Europe during summer and winter Increases in the Mediterranean in DJF and decreases in JJA. Interannual variability: 2-7 oC in the A2 scenario is found over land areas. The B2 scenario is 1-2 oC lower. 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.