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Quaternary Environments Paleoclimate Models

Quaternary Environments Paleoclimate Models. Types of Models. Simplify a system to its basic components Types of Models Physical Models Globe Statistical Models Regression Equations Conceptual Models Flow chart Computer Models GCMs Test Hypotheses. Types of Models.

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Quaternary Environments Paleoclimate Models

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  1. Quaternary EnvironmentsPaleoclimate Models

  2. Types of Models • Simplify a system to its basic components • Types of Models • Physical Models • Globe • Statistical Models • Regression Equations • Conceptual Models • Flow chart • Computer Models • GCMs • Test Hypotheses

  3. Types of Models • Energy Balance Models (EBMs) – Surface temperature as a result of energy balance • Zero-Dimension – Whole Earth • One-Dimension – Earth in zonal bands with latitudinal heat transfer • Two-Dimensions – Lat/Long or Latitude/Altitude changes • Statistical –Dynamical Models (SDMs) • Use parameterized input equations to describe changes through time • Radiative Convective Models (RCMs) • Radiative processes in vertical columns • General Circulation Models (GCMs) • Use physical laws to drive all changes • Coupled Ocean-Atmosphere GCMs

  4. Statistical-Dynamical Model of variations of Northern Hemisphere ice volume over the last 200,000 years forced by CO2 and Insolation

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

  6. Levels of Complexity and Coupling of Ocean-Atmosphere Models

  7. Problems With Current Models • Expense and Time • Resolution • Unknown Quantities • Cloud cover and feedback • Difference in response times between various components of the model • Lacking land surface, cryosphere, biogeochemical cycles, and biome components • Climate System Models (CSMs) being developed

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

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

  10. Model Experiments • Are changes in orbital parameters enough to cause a glacial event? • Insolation as an input • Also needed increased cloudiness, increased soil moister, a shallow mixed layer in the ocean, and lower CO2 • Feedbacks include increased sea ice, lower SSTs in summer, and presence of permanent snow cover on land

  11. Difference in Solar Radiation at the Top of the Atmosphere 115 kya

  12. Modeled Snow Depth in August for 115 kya

  13. Input Parameters for COHMAP Simulation

  14. Output from COHMAP, Split Jet Stream During LGM

  15. Modeling Forward • Models can be tested against paleorecords then these models can be used to predict future change • Multiple model outputs to estimate future change

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

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

  18. Scaling down from a GCM through a Regional Climate Model to the landscape Climatic Research Unit,University of East Anglia http://www.cru.uea.ac.uk/

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