Unformatted text preview: Daisyworld Daisyworld
An Introduction to Systems Chapter 2
Dr. Emily Berndt Fundamentals of the Climate System EAS 253 I. The Systems Approach I.
A. The Essentials of Systems ii. Diverse but interrelated parts called . components components iii. The state of a system is the set of i. attributes that characterize the system at a particular time at I. The Systems Approach I.
B. Couplings ii. The components do not exist in . isolation isolation iii. Couplings are links that transfer i. information between component information I. The Systems Approach I.
C. Feedback Loops C. i. A self-perpetuating mechanism of change and response to that change change ii. Identifying the type of feedback loop ii. Count the number of negative couplings I. The Systems Approach I.
D. Equilibrium States
ii. The equilibrium state will not change unless the . system is disturbed system iiv. A system with a single feedback loop has a stable v. equilibrium state if the feedback loop is negative equilibrium I. The Systems Approach I.
E. Perturbations and Forcings ii. We can learn much by observing how . a system responds to disturbances system iii. Perturbation – a temporary i. disturbance disturbance iii. Forcing – a persistent disturbance The Average Climatic Response to Volcanic Eruptions Volcanic Krakatau (1883) Santa Maria (1902) Agung (1963) El Chichon (1982) Pinatubo (1991) II. The Daisyworld Climate System System
A. A simulation to demonstrate the plausibility of A. the Gaia Hypothesis the B. Two component system
1. 2. Area of white daisy coverage Average surface temperature of planet C. Interrelationships Coverage impacts temperature Temperature impacts growth rate Growth rate impacts daisy coverage
http://www.gingerbooth.com/flash/daisyball/DaisyBall.html II. The Daisyworld Climate System System
D. Characteristics of Daisyworld
Pure white daisies and gray soil Daisies get nutrients and water from soil No clouds or greenhouse gases Amount of sunlight absorbed depends on Amount amount of soil amount Sun is increasing in solar luminosity Sun II. The Daisyworld Climate System System
E. Couplings in Daisyworld ii. Response of Surface Temperature . Changes to Changes in Daisy Coverage Coverage Albedo Reflectivity of a surface, fraction of incident energy Reflectivity reflected reflected More daisies, more sunlight reflected, less More absorbed… absorbed… What type of coupling exists between daisy coverage and temperature? temperature? II. The Daisyworld Climate System System Let’s treat Albedo as a third component of Let’s the system the II. The Daisyworld Climate System System II. The Daisyworld Climate System System
E. Equilibrium States in Daisyworld II. The Daisyworld Climate System System
iii. How do the i. equilibrium states respond to perturbation? to
Perturbation- temporary Perturbationdisturbance disturbance III. External Forcing III.
A. Forcings are different from perturbations B. Increase solar luminosity C. Impact of increasing solar luminosity?
i. ii. Equilibrium temperature evolving to a higher temperature Temperature should warm slower due to the feedback from the daisies III. External Forcing III.
D. Response of couplings to forcing ii. Assume Daisies only respond to temperature .
changes and NOT solar luminosity changes
1. No changes in the parabola (represent surface temperature changes and daisy No coverage) coverage) 2. Changes in the straight line (changes in daisy coverage and temperature) iii. For any amount of daisy coverage, the temperature i. will increase as solar luminosity increase will
1. Indefinite temperature increase 2. Straight graph shifts upward Straight III. External Forcing III.
E. Response of Equilibrium States to E. Forcing Forcing
i. Higher stable equilibrium for temperature and daisy coverage ii. Response to increase solar luminosity is increased daisy coverage iii. Increase in albedo (surface reflectivity) explains why the temperature Increase didn’t rise as much as it would without feedback didn’t iv. Stability limit is lower and les resistant at the new equilibrium III. External Forcing III.
F. Mathematical expression of Daisyworld’s F. behavior behavior ∆Teq = ∆T0 + ∆T f ∆Teq
Temperature change of the new equilibrium state (includes feedback) Temperature change without the feedback effect Temperature change of the feedback effect ∆T f III. External Forcing III.
G. Quantify the strength of the Feedback Effect f= ∆Teq ∆T0 Temperature change with Feedback Temperature change without Feedback IV. The Climate History of Daisyworld Daisyworld V. Lessons of Daisyworld V.
A. A climate system is not passive to climate internal or external influences internal B. The climate regulation system of B. Daisyworld is intelligent Daisyworld C. System adjust to a new equilibrium state D. Thresholds exist in climate systems E. Earth is similar to Daisyworld ...
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