1. Coupled Climate Models OCEAN-ATMOSPHEREINTERACTIONS

2. What is climate? n Different meanings –an external, forcing agent –influence on society and socio-economics –a background norm on which weather is imposed –temperature, rain, and humidity

3. Climatic System 5 Major Components n Hydrosphere n Atmosphere n Cryosphere n Lithosphere n Biosphere

4. Why does climate vary? VARIATIONS IN CLIMATE COMPONENTS

5. Climate Forcings: the basis for change n Forcing: a change on the planetary energy balance system (flux) n 2 separate categories: –External Forcings –Internal Forcings n Human n Natural

6. Climate Forcings: External n Milankovitch Cycles –Eccentricity –Obliquity –Precession n Solar Activity n Comet/meteorite impacts

7. Climate Forcings: Internal Human induced n Greenhouse Gases n Tropospheric Aerosols n Ozone Depletion n Land Surface Changes KNOWN FORCINGS

8. Climate Forcings: Internal Natural n Ocean circulation changes n Volcanic eruptions n Heat Transfer from interior

9. Measurements that Drive the Models n Sea surface temperature n Air temperature and humidity n Wind velocity n Net radiation flux at ocean and underlying surfaces and upper atmospheric boundary n Fluxes of momentum, heat and moisture at the ocean-atmosphere boundary

10. Coupled Climate Model n Combine oceanic and atmospheric models

11. General Circulation Model: GCM n 3-dimensional model –scaling issues

12. General Circulation Model: GCM n Solve for the main features of the atmosphere and ocean through a series of equations

13. Atmospheric GCM

14. AGCM variables n Surface Pressure n 2 horizontal wind components n Temperature n Moisture n Geopotential height

15. AGCM: Physical Processes n Radiative Transfer –daily and annular cycles –short- and long-wave –clouds n Boundary Layer –friction –diurnal temperature and humidity variations

16. AGCM: Physical Processes n Large-scale rainfall n Convection

17. AGCM: Physical Processes n Land Surface Parameterization –gravity wave drag

18. Oceanic GCM n Drivers –Winds –Salinity and density n Detailed schemes –Stronger currents on western sides of basin

19. OGCMs n Swamp Model n Slab Model n Detailed Mixed Layer Model n Dynamic Ocean Model

20. OGCM: Grid

21. Other Schemes n Cyrosphere –hydrologic cycle –albedos n wind and heat n Vegetation –different scales –lack of validation data

22. Coupled Model: AOGCM

23. AOGCM Problems n Time Scales n Grid Scales n Costs

24. AOGCM Solutions n Asynchronous Coupling

25. Conclusion There is a long way to go before we have RELIABLE Models with which to predict CLIMATE and CLIMATE CHANGE …