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So what is a GCM?

So what is a GCM?. GCMs. General Circulation Models Atmospheric GCMs Ocean Representations Specified Sea Surface Temperatures (SSTs) Simple Ocean Models (Slab) Coupled Ocean-Atmos GCMs. GCMs. Global Climate Models Qflux Mixed-Layer Oceans Coupled Dynamic Oceans Sea Ice

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So what is a GCM?

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  1. So what is a GCM?

  2. GCMs • General Circulation Models • Atmospheric GCMs • Ocean Representations • Specified Sea Surface Temperatures (SSTs) • Simple Ocean Models (Slab) • Coupled Ocean-Atmos GCMs

  3. GCMs • Global Climate Models • Qflux Mixed-Layer Oceans • Coupled Dynamic Oceans • Sea Ice • Vegetation (physical) • Ground Hydrology (buckets) • Middle and Upper Atmosphere • Passive Tracer Transports

  4. GCMs • Earth System Models • Coupled and Dynamic Everything • Physiological Vegetation • Dynamic Ice Sheets • Carbon Cycle Modeling

  5. GCMs • Off-Line or Nested Models • Regional Climate Models • Crop Models • Economic Models • Sediment Transport Models • Watershed Models • . • . • .

  6. So what is a GCM?

  7. Unix Scripts FORTRAN Code SnowballEarth_Sim2.R Model II 8/24/2000Owner: Dr. Mark Chandler, chandler@giss.nasa.govGroup: Paleoclimate GroupThis experiment simulates a time period approximately 600 million years ago.Object modules:MainC9DiagC9RadC9FFTC9UTILC9Data input files:7=G8X10_600Ma9=NOV1910.rsf_snowball15=O8X10_600Ma17=25=Modern_OceanTransports19=CD8X10_600Ma23=V8X10_600Ma26=Z8X101_600Ma21=RTAU.G25L1522=RPLK2529=Snowball_Earth_RegionsLabel and Namelist:Snowball_sim2 (Snowball Earth Experiment: 600 million years ago) &INPUTZ TAUI=10176.,IYEAR=1900, KOCEAN=1, SRCOR=.95485638151, S0X=1.,CO2=.31746031746031, USET=0.,TAUE=35040., USESLP=-12., ISTART=3,KCOPY=2,NDPRNT=-1,TAUE=10177.,TAUP=95616., &END C**** INITIALIZE SOME ARRAYS AT THE BEGINNING OF SPECIFIED DAYS 82. fName = './prt/'//JMNTH0(1:3)//CYEAR//'.prt'//LABEL1(1:LLAB1) IF(JDAY.NE.32) GO TO 294 c ** END (CHANGED) JEQ=1+JM/2 83.01 DO 292 J=JEQ,JM 83.02 DO 292 I=1,IM 83.03 292 TSFREZ(I,J,1)=JDAY 83.04 JEQM1=JEQ-1 83.05 DO 293 J=1,JEQM1 83.06 DO 293 I=1,IM 83.07 293 TSFREZ(I,J,2)=JDAY 83.08 GO TO 296 83.09 294 IF(JDAY.NE.213) GO TO 296 83.1 JEQM1=JM/2 83.11 DO 295 J=1,JEQM1 83.12 DO 295 I=1,IM 83.13 295 TSFREZ(I,J,1)=JDAY 83.14 C**** INITIALIZE SOME ARRAYS AT THE BEGINNING OF EACH DAY 83.4 296 DO 297 J=1,JM 83.5 DO 297 I=1,IM 83.51 TDIURN(I,J,1)=1000. 83.511 TDIURN(I,J,2)=-1000. 83.512 TDIURN(I,J,3)=1000. 83.513 TDIURN(I,J,4)=-1000. 83.514 TDIURN(I,J,5)=0. 83.52 TDIURN(I,J,6)=-1000. 83.521 PEARTH=FDATA(I,J,2)*(1.-FDATA(I,J,3)) 83.53 IF(PEARTH.GT.0.) GO TO 297 83.54 TSFREZ(I,J,1)=365. 83.55 TSFREZ(I,J,2)=365. 83.56 297 CONTINUE 83.57 C**** 84. C**** INTEGRATE DYNAMIC TERMS 85. C**** 86. 300 MODD5D=MOD(NSTEP,NDA5D) 87. IF(MODD5D.EQ.0) CALL DIAG5A (2,0) 88.

  8. Atmosphere Oceans Ice Sheets Sea Ice Vegetation A Computer Simulation of the Earth System

  9. The NASA/GISS Family of GCMs: Cartesian Grid General Circulation Models (Henderson-Sellers, 1985) (Hansen et al., 1983)

  10. Primitive Equations in a GCM Conservation Equations Conservation of Energy Conservation of Mass Conservation of Moisture Conservation of MomentumEquation of State

  11. Key State Variables in a GCMhandled by primitive equations • T, TemperatureP, PressureQ, Specific Humidity (Atm. Water Vapor)U, East-West WindsV, North-South Winds

  12. Climate System Parameterizations

  13. Linking Parameterizations andPrimitive Equations

  14. 8°X 10° 4°X 5° 1980’s 1990’s 2°X 2.5° 2000’s Atmospheric Global Climate Model Grid Resolutions

  15. Paul N. Edwards Univ. of Michigan, ca. 2000 The GCM Family Tree GFDL NCAR GISS

  16. Relevant to Science Why use GCMs? Relevant to Society

  17. The “Keeling Curve”: CO2 rise during the 20th Century 380 360 340 Carbon Dioxide (parts per million) 320 300 Mauna Loa Observatory 280 1960 1970 1980 1990 2000 Year Image Credit: NASA Earth Observatory

  18. 20th Century Trend of the Dow Jones Industrials Average Source: Yahoo!, Inc.

  19. CAUSE EFFECT PROCESS PROCESS PROCESS PROCESS PROCESS PROCESS

  20. CAUSE EFFECT Recent Climate Change: Observed Forcings and Observed Results. Verification of models and Analyze processes

  21. 21st Century Global Warming Climate Simulations for IPCC 2007 Report ►Climate Model Sensitivity 2.0-5.0ºC for 2xCO2 (consistent with paleoclimate data & other models) ►Simulations Consistent with 1880-2003 Observations Source: Hansen et al., to be submitted to J. Geophys. Res.

  22. Use of extreme phenomena to validate GCMs Eruption of Mt. Pinatubo

  23. CAUSE EFFECT Future Climate Change: Observed and Estimated Forcings Unknown Results

  24. Instantaneous Doubling of CO2 Transient Doubling of CO2

  25. Dangerous Anthropogenic Influence (DAI) DAI Hansen, 2004

  26. 2050sChange in Surface Air Temperature +2.33 °C

  27. CAUSE EFFECT Past Climate Change: Observed Results Unknown Forcings

  28. CO2 Through Earth History Pliocene, 3mya

  29. Middle Pliocene Sea Level Rise B) A) Modern Shoreline Pliocene Shoreline A) Based upon marine stable isotope records, sequence stratigraphy, and ancient shorelines, mid Pliocene sea level is estimated to be +25 m relative to today. B) This image shows a section of the Orangeburg Scarp in Georgia, dated at 3.5-3.0 Ma. The Orangeburg Scarp suggests a sea level 35±17m relative to today.

  30. Pliocene Temperature Change: 3 MYA +2.13 °C 2050s +2.33 °C

  31. 3 mya 2050s

  32. Circulation System of the World Oceans

  33. Global Surf. Air Temp. Change 1958-2100

  34. Global Warming with Altered Ocean Circulation CO2 Increase + 0.8 OHT Latitude 20% OHT Decrease CO2 Increase + 1 OHT Latitude 0% OHT Change CO2 Increase + 1.2 OHT Latitude 20% OHT Increase

  35. Has it happened before? The warming of the 1930s was more similar to a warming caused by altered ocean heat transports than to greenhouse gas increases. 5-Year Running Mean 90N 3.0 60N 1.4 0.7 30N 0.3 0.1 °C 0.0 0 EQ -0.1 -0.3 30S -0.7 -1.4 60S -3.0 90S 1880 1895 1910 1925 1940 1955 1970 1985 Year

  36. Could it happen again? If the oceans respond in a manner similar to the mid-Pliocene warming then estimates of global warming would be altered significantly in some regions. Regional changes in temperature associated with altered ocean circulation scenarios

  37. Climate@Home Simulation Distribution Simulation Results Collection Scientific Community GSFC GISS Langley Personal Computers School Labs University Clusters DOE NASA NSF EdGCM Model E EdGCM Model E EdGCM Model E GISS Model E GISS Model E GISS Model E Desktop Client Computing Resources National Lab Supercomputing Resources Primary Server Perturbed Physics Ensembles NASA MAP Climate Scientists

  38. The Democratization of Global Climate Modeling The EdGCM Cooperative Project Columbia University and the University of Wisconsin-Madison Support provided by: NSF Paleoclimate Program and NASA High-Performance Computing Program

  39. Scarsdale Teachers Institute, March 3 and 4, 2006

  40. Responsibility for CO2 Emissions and Climate Change

  41. Metrics for “Dangerous” Change Extermination of Animal & Plant Species 1. Extinction of Polar and Alpine Species 2. Unsustainable Migration Rates Ice Sheet Disintegration: Global Sea Level 1. Long-Term Change from Paleoclimate Data 2. Ice Sheet Response Time Regional Climate Change 1. General Statement 2. Droughts/Floods

  42. Status of CO2 Pre-industrial Amount: 280 ppm Present Amount: 382 ppm Maximum Allowable ≤ 450 ppm Rate of Change: +2 ppm/year (and growing)  Maximum Will Be Exceeded!  ‘Geoengineering’ Probably Needed

  43. Methods to Reduce CO2 Emissions 1.Energy Efficiency & Conservation More Efficient Technology Life Style Changes 2.Renewable & CO2-Free Energy Hydro Solar, Wind, Geothermal Nuclear 3.CO2 Capture & Sequestration  No Silver Bullet  All Three are Essential

  44. DEC DEC JAN SST JAN SEA-ICE GCM Initial Condition Data Sets TOPO- GRAPHY SEA LEVEL VEG ATMOSPHERE: TEMPERATURE PRESSURE WATER VAPOR

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