Embed Size (px)
DESCRIPTION
Chapter 3 Daisyworld. Objectives: Albedo Couplings between daisy coverage & T Equilibrium states in Daisyworld Response of Daisyworld to incr. solar output. A view of Daisyworld from outer space. Couplings between daisy coverage & T . T. Daisy coverage. Daisy Coverage. albedo. T. - PowerPoint PPT Presentation
Citation preview
ENSC 425/625 Chapter 3UNBC 1
Chapter 3 Daisyworld
Objectives:•Albedo
•Couplings between daisy coverage & T
•Equilibrium states in Daisyworld
•Response of Daisyworld to incr. solar output
ENSC 425/625 Chapter 3UNBC 2
A view of Daisyworld from outer space
ENSC 425/625 Chapter 3UNBC 3
ENSC 425/625 Chapter 3UNBC 4
Couplings between daisy coverage & T •Incr. daisy coverage of planet => decr. T.
T
Daisy coverage
DaisyCoverage T
DaisyCoverage albedo T
ENSC 425/625 Chapter 3UNBC 5
•Daisies can live between a min.T & a max. T
T
Dai
sy c
over
age
min. max.
optimum
T daisycoverage T daisy
coverage
ENSC 425/625 Chapter 3UNBC 6
•Intersection of 2 curves means the 2 effects are balanced => equilibrium points P1 & P2.
T
Dai
sy c
over
age
Effects of T ondaisy coverage
P1
Effects of daisy coverage on T
P2
T daisycoverage T daisy
coverage
ENSC 425/625 Chapter 3UNBC 7
Feedback loops
P1
Effects of daisy coverage on T
P2 T
Dai
sy c
over
age
Effects of T ondaisy coverage
ENSC 425/625 Chapter 3UNBC 8
• Perturb daisy coverage at P1 => sys. returns to P1 (stable equil. pt.)
T
Dai
sy c
over
age
P1
P2
A large perturb. => daisies all die from extreme T
ENSC 425/625 Chapter 3UNBC 9
•Large incr. in daisy cover => very low T => decr. in daisy cov. => very high T => lifeless.
P1
T
Dai
sy c
over
age
P2
ENSC 425/625 Chapter 3UNBC 10
•From P2, incr. daisy cov. => decr. T => further incr. in daisy cov. => converge to P1
P1
T
Dai
sy c
over
age
P2unstable equilib. pt.
T daisycoverage
ENSC 425/625 Chapter 3UNBC 11
ENSC 425/625 Chapter 3UNBC 12
Gradual incr. in solar luminosity
T
Dai
sy c
over
age
P1
P2Teq
To Tf
P1
P2
The effect of T on Daisy unchanged
For any particular value of daisy cov., T incr.
ENSC 425/625 Chapter 3UNBC 13
•As solar lum. incr., T incr. => daisy cov. incr.
•Eventually, daisies cannot expand, but T keeps incr.
=> daisies dying => decr. albedo => rapid T incr.
(pos. feedback) => daisies extinct. Solar luminosity
T
% daisy cov.
Min. T for daisy survival
Max. T for daisy survival
ENSC 425/625 Chapter 3UNBC 14
Lessons from Daisyworld•Despite change in forcing, climate sys. can
counter part of the change by negative feedback loops.
