Experiment with the Daisy World (“Daisy Ball”)
Daisy World is a very simple model of a system with external forcing (“solar luminosity”) and feedbacks
(white and black daisies).
Solar luminosity increases with time, and the system tries to keep the temperature from rising (“stable
climate”) by changing the area covered by white and black daisies. White daisies prefer warmer
temperatures and have high albedo, black daisies prefer colder temperatures and have low albedo. See
notes for the “Climate Feedbacks” lecture and online description at
http://gingerbooth.com/flash/daisyball/ for more details.
For this assignment, use the online model at http://gingerbooth.com/flash/daisyball/DaisyBall.html. An
example of a “climate simulation” is in the Figure 1 below. On the left of this figure, you see two graphs:
(top plot) area taken by white (white line) and black (black line) daisies, and area that is taken by bare
land (brown line);
(bottom plot) temperature of the Daisy World: actual temperature (purple) and temperature this planet
would have if there were no daisies (brown).
As the time passes, the solar luminosity increases in both plots.
FIGURE 1:
For the assignment:
1) Run the standard case (default parameters) and describe what you see 2) Now change the system parameters by clicking on “Advanced” button. You will see several
options (Figure 2). Change one of the parameters: albedo of black/white daisies, how fast
luminosity changes, daisy “deathrate” (minimum area covered by daisies), etc. Describe how the
system behavior is different from the standard case. Explain what you see.
FIGURE 2:
