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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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slide2

GCMs

  • General Circulation Models
  • Atmospheric GCMs
  • Ocean Representations
  • Specified Sea Surface Temperatures (SSTs)
  • Simple Ocean Models (Slab)
  • Coupled Ocean-Atmos GCMs
slide3

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
slide4

GCMs

  • Earth System Models
  • Coupled and Dynamic Everything
  • Physiological Vegetation
    • Dynamic Ice Sheets
    • Carbon Cycle Modeling
slide5

GCMs

  • Off-Line or Nested Models
  • Regional Climate Models
  • Crop Models
  • Economic Models
  • Sediment Transport Models
  • Watershed Models
  • .
  • .
  • .
slide7

Unix Scripts

FORTRAN Code

SnowballEarth_Sim2.R Model II 8/24/2000Owner: Dr. Mark Chandler, [email protected]: 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.

slide8

Atmosphere

Oceans

Ice Sheets

Sea Ice

Vegetation

A Computer Simulation of the Earth System

primitive equations in a gcm
Primitive Equations in a GCM

Conservation Equations Conservation of Energy Conservation of Mass Conservation of Moisture Conservation of MomentumEquation of State

key state variables in a gcm handled by primitive equations
Key State Variables in a GCMhandled by primitive equations
  • T, TemperatureP, PressureQ, Specific Humidity (Atm. Water Vapor)U, East-West WindsV, North-South Winds
slide14

8°X 10°

4°X 5°

1980’s

1990’s

2°X 2.5°

2000’s

Atmospheric

Global Climate Model

Grid Resolutions

the gcm family tree

Paul N. Edwards

Univ. of Michigan, ca. 2000

The GCM Family Tree

GFDL

NCAR

GISS

slide16

Relevant to Science

Why use GCMs?

Relevant to Society

slide17

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

slide19

20th Century Trend of the

Dow Jones Industrials Average

Source: Yahoo!, Inc.

slide20

CAUSE

EFFECT

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

slide21

CAUSE

EFFECT

Recent Climate Change:

Observed Forcings and Observed Results.

Verification of models and

Analyze processes

21 st century global warming
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.

slide24

CAUSE

EFFECT

Future Climate Change:

Observed and Estimated Forcings

Unknown Results

slide25

Instantaneous

Doubling of CO2

Transient

Doubling of CO2

slide29

CAUSE

EFFECT

Past Climate Change:

Observed Results

Unknown Forcings

slide31

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.

pliocene temperature change 3 mya
Pliocene Temperature Change: 3 MYA

+2.13 °C

2050s

+2.33 °C

slide33

3 mya

2050s

slide36

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

slide37

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

slide38

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

slide39

[email protected]

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

slide40

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

slide43
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

slide44
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

slide45
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

gcm initial condition data sets

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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