Quaternary EnvironmentsQuaternary EnvironmentsPaleoclimate ModelsPaleoclimate Models

Types of ModelsTypes of Models Simplify a system to its basic componentsSimplify a system to its basic components Types of ModelsTypes of Models

Physical ModelsPhysical Models GlobeGlobe

Statistical ModelsStatistical Models Regression EquationsRegression Equations

Conceptual ModelsConceptual Models Flow chartFlow chart

Computer ModelsComputer Models GCMsGCMs

Test HypothesesTest Hypotheses

Types of ModelsTypes of Models Energy Balance Models (EBMs) – Surface Energy Balance Models (EBMs) – Surface

temperature as a result of energy balancetemperature as a result of energy balance Zero-Dimension – Whole EarthZero-Dimension – Whole Earth One-Dimension – Earth in zonal bands with latitudinal heat One-Dimension – Earth in zonal bands with latitudinal heat

transfertransfer Two-Dimensions – Lat/Long or Latitude/Altitude changesTwo-Dimensions – Lat/Long or Latitude/Altitude changes

Statistical –Dynamical Models (SDMs)Statistical –Dynamical Models (SDMs) Use parameterized input equations to describe changes Use parameterized input equations to describe changes

through timethrough time Radiative Convective Models (RCMs)Radiative Convective Models (RCMs)

Radiative processes in vertical columnsRadiative processes in vertical columns General Circulation Models (GCMs)General Circulation Models (GCMs)

Use physical laws to drive all changesUse physical laws to drive all changes Coupled Ocean-Atmosphere GCMsCoupled Ocean-Atmosphere GCMs

Statistical-Dynamical Model of variations of Statistical-Dynamical Model of variations of Northern Hemisphere ice volume over the last Northern Hemisphere ice volume over the last 200,000 years forced by CO200,000 years forced by CO22 and Insolation and Insolation

Schematic Diagram of atmosphere and ocean computational boxes in a coupled GCM

Levels of Complexity and Coupling of Levels of Complexity and Coupling of Ocean-Atmosphere ModelsOcean-Atmosphere Models

Problems With Current ModelsProblems With Current Models Expense and TimeExpense and Time

ResolutionResolution Unknown Quantities Unknown Quantities

Cloud cover and feedbackCloud cover and feedback Difference in response times between various Difference in response times between various

components of the modelcomponents of the model Lacking land surface, cryosphere, biogeochemical Lacking land surface, cryosphere, biogeochemical

cycles, and biome componentscycles, and biome components Climate System Models (CSMs) being developedClimate System Models (CSMs) being developed

http://www.cru.uea.ac.uk/cru/info/scen/

Estimated Response and Equilibrium Times for Estimated Response and Equilibrium Times for Different Components of the Climate SystemDifferent Components of the Climate System

Model ExperimentsModel Experiments Are changes in orbital parameters enough Are changes in orbital parameters enough

to cause a glacial event?to cause a glacial event? Insolation as an inputInsolation as an input Also needed increased cloudiness, increased Also needed increased cloudiness, increased

soil moister, a shallow mixed layer in the soil moister, a shallow mixed layer in the ocean, and lower COocean, and lower CO22

Feedbacks include increased sea ice, lower Feedbacks include increased sea ice, lower SSTs in summer, and presence of permanent SSTs in summer, and presence of permanent snow cover on landsnow cover on land

Difference in Solar Radiation at the Top of Difference in Solar Radiation at the Top of the Atmosphere 115 kyathe Atmosphere 115 kya

Modeled Snow Depth in August for 115 kyaModeled Snow Depth in August for 115 kya

Input Parameters for COHMAP Input Parameters for COHMAP SimulationSimulation

Output from COHMAP, Split Jet Output from COHMAP, Split Jet Stream During LGMStream During LGM

Modeling ForwardModeling Forward Models can be tested against paleorecords Models can be tested against paleorecords

then these models can be used to predict then these models can be used to predict future changefuture change

Multiple model outputs to estimate future Multiple model outputs to estimate future changechange

http://www.cccma.bc.ec.gc.ca/models/cgcm2.shtml

http://www.cccma.bc.ec.gc.ca/models/cgcm2.shtml

Two Environment Canada models showing change from 1971-1990 to 2041-2060. Differences are based on a change in the depth and vigor of vertical mixing in the Southern Ocean

Climatic Research Unit, University of East Angliahttp://www.cru.uea.ac.uk/

Scaling down from a GCM Scaling down from a GCM through a Regional Climate through a Regional Climate Model to the landscapeModel to the landscape