2-2: Climate Models

Pre-Class Preparation

Objectives

• To identify the basic principles used to construct climate models.
• To understand the strengths and weaknesses of climate models.

Procedure

1. Read the learning unit.

   Class images

2. Take the learning unit quiz. Quizzes are available from your portfolio. You may access your portfolio via the list of students participating in this years course, as represented by the icon below.
   
   
3. Additional Required Reading. Although you are not ultimately responsible for content listed in this section, we encourage you to fully explore the links in order to provide a better scope on the upcoming class discussion.

   	How climate models work. From UNEP.
   	Houghton, J. T., L. G. Meira Filho, B. A. Callander N. Harris, A. Kattenberg, and K. Maskell, 1996: Climate Change 1995. The Science of Climate Change. Cambridge University Press, pp 236-245.
   	Houghton, J. T., G. J. Jenkins, and J. J. Ephraums, 1990: Climate Change, The IPCC Scientific Assessment. Cambridge University Press. p. 80-89.

Class Discussion

• Problem to ponder...
  

• Class Discussion Summary: by classmate Matt Dickson

  In class we talked more about climate modeling. We discussed the results of the models. When using the raw data from the computers perception is hard to predict, while the temperature is easier it is just a little bit high when compared to the actual temperatures. In some circumstances the models do not do a very good job. We looked at different models and compared how accurate each of them is. There is no clear best model, some work better in different areas and conditions. The average of all the models usually is the best to use when predicting the future climate. There is always varying circumstances that are not included in the models. The models do a good job including slow climate changes such as El Nino and volcanic eruptions. There are two types of models. The first is equilibrium model; it uses CO₂ in the atmosphere as a sudden occurrence in the future. The transient model uses the increase of CO₂ in the atmosphere as a gradual occurrence. This model is started in the past and taken to the future, sometimes a 200-year span is used. It can take up to a year to get results from this model.

  We also talked about how evaporation of water from the soil is always occurring no matter how dry the soil is. Roots help the process by bringing water up to the surface; thus keeping the soil temperature down. This evaporation also effects the air temperature. The vegetation on the soil and soil type effect temperature. Practices such as cutting trees down and cement effect temperature.

Post-Class Activities

• Participate in the electronic dialog. Use this forum for:
  • continuing class discussion;
  • posing new questions to students or the instructor;
  • responding to issues/questions raised by students in class/electronic dialog.

  Visitor Access (Visitors are welcome to participate in the dialog. Just click on the icon below)	Student Access (Students must post all dialog from their portfolio. Click on the icon below to access the student list.)

• Recommended Reading Materials

  	Cloud Catalog at the University of Illinois Weather Machine
  	Cloud Radiative Processes, NASA
  	Fractal Cloud Animations, California
  	Cess, R. D., et al., 1995: Absorption of solar radiation by clouds: observations vs. models. Science 267, 496-499.
  	Houghton, J.T., G.J. Jenkins, J.J. Ephraums, eds, 1990: 1990 Intergovernment Panel on Climate Change, Cambridge University Press, 77-80.
  	Kerr, Richard A., 1995: Darker clouds promise brighter future for climate models. Science 267, 454.
  	Lashof, D.A., 1989: The dynamic greenhouse: Feedback processes that may influence future concentrations of atmospheric trace gases and climatic change. Climate Change 14, 213-242.
  	Ramanathan, V., et al., 1995: Warm pool heat budget and shortwave cloud forcing: a missing physics? Science 267, 499-503.

• References

  	Intergovernmental Papers on Stabilization and Models
  	Dickinson, R. E., 1995: Walter Orr Robers Lecuture - Land surface processes and climate modeling. Bulletin of the American Meteorological Society 76, 1445-1448
  	Henderson-sellers, A., and K. McGuffie, 1987: A Climate Modeling Primer. John Wiley & Sons. New York. 217 pp.
  	McGuffie, K., and A. Henderson-Sellers, 1997: A Climate Modelling Primer. Second Edition. John Wiley & Sons. New York. 253 pp.
  	Kerr, Richard A., 1997: Greenhouse Forecasting Still Cloudy. Science 276, 1040-1042.
  	Kerr, Richard A., 1997: Model Gets it Right--Without Fudge Factors. Science 276, 1041.
  	Trenberth, K.,1997: The Use and Abuse of Climate Models. Nature 386, 131-133.
  	Zeng, Xubin, R.A. Pielke, R. Eykholt, 1990: Chaos in Daisyworld. Tellus 4, 309-318.