{UTF-8}
absorbed luminosity=
	solar luminosity*(1-planet's average albedo)
	~	
	~		|

actual black growth rate=
	indicated black growth rate*growth reduction multiplier
	~	
	~		|

actual white growth rate=
	indicated white growth rate*growth reduction multiplier
	~	
	~		|

black albedo=
	0.25
	~	
	~		|

black albedo difference=
	planet's average albedo-black albedo
	~	
	~		|

black daisy area= INTEG (
	black growth-black decay,
		250)
	~	
	~		|

black decay=
	black daisy area*decay rate
	~	
	~		|

black growth=
	black daisy area*actual black growth rate
	~	
	~		|

black growth rate multiplier from temperature deviation=
	MAX(0,1-0.003265*black temperature deviation^2)
	~	
	~	This is the parabolic relationship shown in eqt. 3 on page 285 of Watson \
		and Lovelock
	|

black temperature deviation=
	temperature near black area-optimum temperature
	~	
	~		|

black warming effect=
	20*black albedo difference
	~	
	~		|

decay rate=
	0.3
	~	
	~	30%/yr is the value in Watson and Lovelock
	|

empty area= INTEG (
	black decay+white decay-black growth-white growth,
		500)
	~	
	~		|

empty area albedo=
	0.5
	~	
	~		|

fr black=
	black daisy area/1000
	~	
	~		|

fr empty=
	empty area/1000
	~	
	~		|

fr white=
	white daisy area/1000
	~	
	~		|

"growth rate @ optimum temperature"=
	1
	~	
	~	100%/yr is the growth rate if the flowers experience the optimum \
		temperature.  This is the peak of parabolic curve in Fig 11.1
	|

growth reduction multiplier=
	empty area/total area
	~	
	~	this creates a linear reduction in the growth rate.
	|

indicated black growth rate=
	"growth rate @ optimum temperature"*black growth rate multiplier from temperature deviation
	~	
	~		|

indicated white growth rate=
	"growth rate @ optimum temperature"*white growth rate multiplier from temperature deviation
	~	
	~		|

new luminosity=
	1.25
	~	
	~	1.25 is used in the book;  this variable is a slider on the 2nd view
	|

optimum temperature=
	22.5
	~	
	~	Lovelock's daisies grow best when they experience 22.5 degrees C.
	|

planet's average albedo=
	black albedo*fr black+white albedo*fr white+empty area albedo*fr empty
	~	
	~		|

planet's average temperature=
	(((917000*absorbed luminosity)/5.67e-005)^0.25)-273
	~	
	~	This formula taken from Eldon's implementation, and it looks like the \
		1/4th root less 273 degrees comes from eqt 4 on page 285 of the Watson and \
		Lovelock paper.
	|

solar luminosity=
	IF THEN ELSE(Time>year of jump , new luminosity , 1 )
	~	
	~	this is the exogenous input.  It jumps from 1.0 to 1.25 in the year 2010.  \
		We can play with the year of the jump on the 2nd view
	|

temperature near black area=
	planet's average temperature+black warming effect
	~	
	~		|

temperature near white area=
	planet's average temperature-white cooling effect
	~	
	~		|

total area=
	1000
	~	
	~	the total is 1,000 acres.  notice that the iniital values of the three \
		stocks adds to 1,000 acres
	|

white albedo=
	0.75
	~	
	~		|

white albedo difference=
	white albedo-planet's average albedo
	~	
	~		|

white cooling effect=
	20*white albedo difference
	~	
	~	If white albedo is 0.75 and the planet's average albedo is 0.50, then the \
		difference is 0.25.  Multiply by 20 degrees, and the cooling effect would \
		be 5 degrees C.
	|

white daisy area= INTEG (
	white growth-white decay,
		250)
	~	
	~		|

white decay=
	white daisy area*decay rate
	~	
	~		|

white growth=
	white daisy area*actual white growth rate
	~	
	~		|

white growth rate multiplier from temperature deviation=
	MAX(0,1-0.003265*white temperature deviation^2)
	~	
	~	This is the parabolic relationship shown in eqt. 3 on page 285 of Watson \
		and Lovelock
	|

white temperature deviation=
	temperature near white area-optimum temperature
	~	
	~		|

year of jump=
	2010
	~	
	~		|

********************************************************
	.Control
********************************************************~
		Simulation Control Parameters
	|

FINAL TIME  = 2040
	~	Year
	~	The final time for the simulation.
	|

INITIAL TIME  = 2000
	~	Year
	~	The initial time for the simulation.
	|

SAVEPER  = 
        TIME STEP
	~	Year [0,?]
	~	The frequency with which output is stored.
	|

TIME STEP  = 0.25
	~	Year [0,?]
	~	The time step for the simulation.
	|

\\\---/// Sketch information - do not modify anything except names
V300  Do not put anything below this section - it will be ignored
*View of the model
$192-192-192,0,Times New Roman|12||0-0-0|0-0-0|0-0-255|-1--1--1|-1--1--1|96,96,5
10,1,white daisy area,429,94,44,53,3,131,0,24,0,2,0,0,0-0-0,0-0-0,|16|B|0-0-0
10,2,empty area,730,87,87,42,3,131,0,24,0,2,0,0,0-0-0,0-0-0,|16|B|0-0-0
10,3,black daisy area,1057,91,44,50,3,131,0,24,0,2,0,0,0-0-0,0-0-0,|16|B|0-0-0
1,4,6,2,4,0,0,22,0,0,0,-1--1--1,,1|(610,56)|
1,5,6,1,100,0,0,22,0,0,0,-1--1--1,,1|(519,56)|
11,6,380,572,56,6,8,34,3,0,0,1,0,0,0
10,7,white decay,572,75,38,11,40,3,0,0,-1,0,0,0
1,8,10,2,4,0,0,22,0,0,0,-1--1--1,,1|(871,64)|
1,9,10,3,100,0,0,22,0,0,0,-1--1--1,,1|(975,64)|
11,10,556,931,64,6,8,34,3,0,0,1,0,0,0
10,11,black decay,931,83,39,11,40,3,0,0,-1,0,0,0
10,12,decay rate,714,16,34,11,8,3,0,0,0,0,0,0
1,13,12,7,1,0,0,0,0,64,0,-1--1--1,,1|(640,26)|
1,14,12,11,1,0,0,0,0,64,0,-1--1--1,,1|(826,26)|
1,15,1,7,1,0,0,0,0,64,0,-1--1--1,,1|(481,35)|
1,16,3,11,1,0,0,0,0,64,0,-1--1--1,,1|(991,49)|
10,17,growth reduction multiplier,730,193,47,23,8,131,0,0,0,0,0,0
1,18,2,17,1,0,0,0,0,64,0,-1--1--1,,1|(697,181)|
10,19,total area,868,174,30,11,8,3,0,0,0,0,0,0
1,20,19,17,1,0,0,0,0,64,0,-1--1--1,,1|(792,149)|
1,21,23,1,4,0,0,22,0,0,0,-1--1--1,,1|(515,105)|
1,22,23,2,100,0,0,22,0,0,0,-1--1--1,,1|(606,105)|
11,23,684,564,105,6,8,34,3,0,0,1,0,0,0
10,24,white growth,564,124,41,11,40,3,0,0,-1,0,0,0
1,25,27,3,4,0,0,22,0,0,0,-1--1--1,,1|(967,106)|
1,26,27,2,100,0,0,22,0,0,0,-1--1--1,,1|(863,106)|
11,27,572,916,106,6,8,34,3,0,0,1,0,0,0
10,28,black growth,916,125,42,11,40,3,0,0,-1,0,0,0
10,29,actual white growth rate,517,211,38,19,8,3,0,0,0,0,0,0
10,30,actual black growth rate,953,195,39,19,8,3,0,0,0,0,0,0
1,31,29,24,1,0,0,0,0,64,0,-1--1--1,,1|(538,181)|
1,32,30,28,1,0,0,0,0,64,0,-1--1--1,,1|(932,162)|
1,33,1,24,1,0,0,0,0,64,0,-1--1--1,,1|(504,150)|
1,34,3,28,1,0,0,0,0,64,0,-1--1--1,,1|(966,145)|
10,35,indicated white growth rate,502,275,48,19,8,3,0,0,0,0,0,0
10,36,indicated black growth rate,968,269,48,19,8,3,0,0,0,0,0,0
1,37,35,29,1,0,0,0,0,64,0,-1--1--1,,1|(524,245)|
1,38,36,30,1,0,0,0,0,64,0,-1--1--1,,1|(977,235)|
1,39,17,29,1,0,0,0,0,64,0,-1--1--1,,1|(658,225)|
1,40,17,30,1,0,0,0,0,64,0,-1--1--1,,1|(807,222)|
10,41,"growth rate @ optimum temperature",748,283,68,19,8,3,0,0,0,0,0,0
10,42,white growth rate multiplier from temperature deviation,505,369,86,19,8,3,0,0,0,0,0,0
10,43,black growth rate multiplier from temperature deviation,965,350,86,19,8,3,0,0,0,0,0,0
1,44,42,35,1,0,0,0,0,64,0,-1--1--1,,1|(521,341)|
1,45,43,36,1,0,0,0,0,64,0,-1--1--1,,1|(977,319)|
1,46,41,35,1,0,0,0,0,64,0,-1--1--1,,1|(681,257)|
1,47,41,36,1,0,0,0,0,64,0,-1--1--1,,1|(824,262)|
10,48,white temperature deviation,449,438,57,19,8,3,0,0,0,0,0,0
10,49,black temperature deviation,858,420,58,19,8,3,0,0,0,0,0,0
1,50,48,42,1,0,0,0,0,64,0,-1--1--1,,1|(492,439)|
1,51,49,43,1,0,0,0,0,64,0,-1--1--1,,1|(871,386)|
10,52,optimum temperature,695,384,39,19,8,3,0,0,0,0,0,0
10,53,temperature near white area,552,513,54,19,8,3,0,0,0,0,0,0
10,54,temperature near black area,898,491,54,19,8,3,0,0,0,0,0,0
1,55,53,48,1,0,0,0,0,64,0,-1--1--1,,1|(466,485)|
1,56,52,48,1,0,0,0,0,64,0,-1--1--1,,1|(617,442)|
1,57,52,49,1,0,0,0,0,64,0,-1--1--1,,1|(743,421)|
1,58,54,49,1,0,0,0,0,64,0,-1--1--1,,1|(893,453)|
10,59,planet's average temperature,714,483,51,19,8,3,0,0,0,0,0,0
10,60,absorbed luminosity,710,588,32,19,8,3,0,0,0,0,0,0
10,61,solar luminosity,848,610,48,25,8,131,0,24,0,0,0,0,0-0-0,0-0-0,|14|BI|0-0-0
10,62,Time,746,636,26,11,8,2,0,3,-1,0,0,0,128-128-128,0-0-0,|12||128-128-128
1,63,62,61,1,0,0,0,0,64,0,-1--1--1,,1|(788,644)|
1,64,61,60,1,0,0,0,0,64,0,-1--1--1,,1|(812,593)|
1,65,60,59,1,0,0,0,0,64,0,-1--1--1,,1|(647,556)|
1,66,59,53,1,0,0,0,0,64,0,-1--1--1,,1|(621,464)|
1,67,59,54,1,0,0,0,0,64,0,-1--1--1,,1|(811,463)|
10,68,white cooling effect,390,551,42,19,8,3,0,0,0,0,0,0
10,69,black warming effect,1038,544,47,19,8,3,0,0,0,0,0,0
1,70,68,53,1,0,0,0,0,64,0,-1--1--1,,1|(438,525)|
1,71,69,54,1,0,0,0,0,64,0,-1--1--1,,1|(998,502)|
10,72,white albedo difference,483,664,41,19,8,3,0,0,0,0,0,0
10,73,black albedo difference,982,634,42,19,8,3,0,0,0,0,0,0
1,74,72,68,1,0,0,0,0,64,0,-1--1--1,,1|(409,639)|
1,75,73,69,1,0,0,0,0,64,0,-1--1--1,,1|(1053,602)|
10,76,planet's average albedo,698,677,51,19,8,3,0,0,0,0,0,0
1,77,76,60,1,0,0,0,0,64,0,-1--1--1,,1|(681,640)|
10,78,white albedo,461,748,41,11,8,3,0,0,0,0,0,0
1,79,78,72,1,0,0,0,0,64,0,-1--1--1,,1|(474,695)|
1,80,76,72,1,0,0,0,0,64,0,-1--1--1,,1|(631,642)|
10,81,black albedo,1010,738,41,11,8,3,0,0,0,0,0,0
1,82,76,73,1,0,0,0,0,64,0,-1--1--1,,1|(817,684)|
1,83,81,73,1,0,0,0,0,64,0,-1--1--1,,1|(1024,723)|
10,84,empty area albedo,896,698,58,11,8,3,0,0,0,0,0,0
10,85,white daisy area,500,808,60,11,8,2,0,3,-1,0,0,0,128-128-128,0-0-0,|12||128-128-128
10,86,black daisy area,1028,805,41,19,8,2,0,3,-1,0,0,0,128-128-128,0-0-0,|12||128-128-128
10,87,empty area,762,812,45,11,8,2,0,3,-1,0,0,0,128-128-128,0-0-0,|12||128-128-128
1,88,84,76,1,0,0,0,0,64,0,-1--1--1,,1|(802,698)|
1,89,78,76,1,0,0,0,0,64,0,-1--1--1,,1|(562,705)|
10,90,fr white,638,769,25,11,8,3,0,0,0,0,0,0
10,91,fr black,904,765,25,11,8,3,0,0,0,0,0,0
10,92,fr empty,718,757,27,11,8,3,0,0,0,0,0,0
1,93,85,90,0,0,0,0,0,64,0,-1--1--1,,1|(568,788)|
1,94,86,91,1,0,0,0,0,64,0,-1--1--1,,1|(967,812)|
1,95,87,92,1,0,0,0,0,64,0,-1--1--1,,1|(733,793)|
1,96,90,76,1,0,0,0,0,64,0,-1--1--1,,1|(661,732)|
1,97,91,76,1,0,0,0,0,64,0,-1--1--1,,1|(821,775)|
1,98,92,76,1,0,0,0,0,64,0,-1--1--1,,1|(703,715)|
1,99,81,76,1,0,0,0,0,64,0,-1--1--1,,1|(857,735)|
12,100,0,759,859,335,19,3,132,0,0,-1,2,0,0
this View of Vensim Daisyworld:  Set up for Scenario #1:  Solar Luminosity jumps to 1.25 in 2010;  
10,101,year of jump,960,589,60,11,8,131,0,0,0,0,0,0
1,102,101,61,1,0,0,0,0,64,0,-1--1--1,,1|(915,570)|
10,103,new luminosity,769,531,46,11,8,3,0,0,0,0,0,0
1,104,103,61,1,0,0,0,0,64,0,-1--1--1,,1|(823,559)|
12,105,0,758,912,335,19,3,132,0,0,-1,2,0,0
go to next view to experiment with the different years when the solar luminosity increases. 
\\\---/// Sketch information - do not modify anything except names
V300  Do not put anything below this section - it will be ignored
*Experiment with the model
$192-192-192,0,Times New Roman|12||0-0-0|0-0-0|0-0-255|-1--1--1|-1--1--1|96,96,5
12,1,0,459,354,430,350,3,188,0,0,1,0,0,0
temperatures
12,2,0,1020,192,118,48,3,252,0,0,0,0,0,0
year of jump,2005,2025,1
12,3,0,1026,327,115,46,3,252,0,0,0,0,0,0
new luminosity,1.05,1.4,0.01
12,4,0,1026,440,125,38,3,132,0,24,-1,3,0,0,0-0-0,0-0-0,|16|B|0-0-0
This view can be used to test for the span of control. 
12,6,0,1023,83,114,47,3,4,0,24,-1,4,0,0,0-0-0,0-0-0,|24|B|0-0-0
Daisyworld in Vensim
12,7,0,1027,584,107,91,3,4,0,0,0,1,0,0
 Note: The results will not be an identical match to Fig 11.7 because the model in the book includes a lagged effect of temperature.  I left the lag out of this model since we do not cover lags until chapter 14.
///---\\\
:GRAPH temperatures
:TITLE Graph Similar to Fig 11.6 in Book
:SCALE
:VAR solar luminosity
:Y-MIN 0
:Y-MAX 4
:LINE-WIDTH 2
:SCALE
:VAR planet's average temperature
:Y-MIN 0
:Y-MAX 50
:LINE-WIDTH 4
:VAR temperature near white area
:LINE-WIDTH 2
:VAR temperature near black area
:LINE-WIDTH 2
:L<%^E!@
1:Current.vdf
1:C:\Andy's Documents\Book 2nd Ed\AA Chapters\Ch 11 Daisyworld\Current.vdf
9:Current
23:0
15:0,0,0,0,0,0
19:5,1
27:2,
4:Time
5:black albedo difference
24:2000
25:2040
26:2040