# geography lab 7

gabdar

Lab #6 Climate Modeling of “DaisyWorld” (21 pts)

The “DaisyWorld” Climate Model

James Lovelock and others developed the parable of DaisyWorld to explain the role of life in maintaining system wide climate equilibrium on Earth. DaisyWorld is a hypothetical planet where the only organisms were daisies.   Originally, DaisyWorld was used as a thought exercise to illustrate feedback mechanisms in a simplified global climate system.  Climatologists and environmental scientists have taken this process further and developed computer models to test the relationship between life and non-biological influences on a global climate system.  In this lab we will see examples of feedback in a very simplified global climate system as represented in a computer model.

DaisyWorld

DaisyWorld represents an extremely simple model of a self-regulating global climate system.  Assume an earthlike planet (DaisyWorld) that supports only one type of organism – Daisies. Also assume that the planet has no clouds in its atmosphere or any significant greenhouse gases. Given this situation, the temperature of the atmosphere is a function of the albedo characteristics of its surface (an extremely simple situation). Depending on the species, the daisies come in different colors and therefore have different albedo characteristics. Moreover, bare ground has its own albedo value.

You can probably see where this is going. Temperature in the planet’s lower atmosphere is a function of the albedo characteristics of the surface.   The number and type of daisies influence climate (the only climate variable is temperature). Note however, that the daisies ability to reproduce is a function of the temperature.  They die at a constant rate, so a low rate of reproduction will eventually lead to their disappearance (i.e. extinction).

Visit Ginger Booth’s Daisyworld website at the following address: http://gingerbooth.com/courseware/daisy.html

Carefully explore the website and as a group, answer the following questions on a separate piece of paper. Answers for this Lab must be typed:

1)    Run the Black Only and the White Only scenarios.  How long in these scenarios was the climate in equilibrium? What defines “equilibrium” in this modeled system? Identify and describe the feedback processes in this system.  What is the equilibrium temperature in each of these scenarios? (5 points)

2) What is the albedo of black daisies, white daisies and the barren ground in the Black Only and the White Only scenarios? (1 points)

3) Compare the scenarios Black and White and 6 Color.  What is different about the parameters in these two scenarios (be specific as possible here)? How and why are the results different in terms of the amount of time the planet’s climate is in equilibrium?  (3 points)

4) Try to adjust the albedo parameters and explore other scenarios in such a way as to maximize the time that the climate is in equilibrium (albedo settings however cannot be 0 or 1.0). (3 points)

5) Compare Daisyworld and Daisyball. What are the differences between these models? Which is a more realistic model and why? Do they produce different results given the same initial conditions (run Black and White on both)? (3 points)

6) Suggest one additional process and/or relationship to Daisyworld that represents a biological or non-biological factor in climate change (beyond those represented on this website).  Indicate how this factor/process contributes feedback to the system. Be sure to comment on whether this new factor or variable adds stability or instability to the climate system. Introduce a factor that is realistic from our readings or the videos we have seen. (6 points)

• 6 years ago
• 15