184
9. Modeling Eelgrass (Zostera marina L.) Distributions in Great Bay
loss_of_leaves = IF Discarded_shoot >0 THEN
(Nr_of_leaves /{PI_discard))
+Loss_of_shoots*lvs-per_shoot ELSE
Loss_of_shoots*lvs-per_shoot
OUTFLOW FROM: Nr_of_leaves (IN SECTOR: Plant Density
Sector)
Day = Mod{TIME,366)
Light = Surface_light*-Per_of_max_Light
Photo-period = 7.639437*h_angle
Rand = RANDOM{0,98)
SDCLN = 0 .00678+0.39762*COS{0 .0172142*{Day-172))
+0.00613*SIN{0.0172142*{Day-172))0.00661*COS{0 .034428*{Day-172))0.00159*SIN{0.034428*{Day-172))
Surface_light = (1Skew_weather)*{37.665+23.275*sin{0.016252*Day+5.0881))
temperature = 16 .744+7.2337*SIN{0 .017216*Day+4.493)
-Latitude = 55
-Max_Shoot_density = 1000
-Per_of_max_Light = 1 {if TIME>730 or TIME<366 then 1
else 0.4}
Decline = GRAPH{SDCLN)
(-1.00, -1.57), (-0.75, -1.12), (-0.5, -0.644) , (-0 .25,
-0.305), (O .OO, 0.00), (0.25, 0.305), (0 .5, 0.644),
(0 .75, 1.12) , (1.00, 1.57)
h_angle = GRAPH{-TAN{-Latitude*0.0174533)*TAN{Decline))
(-1.00, 3 .14), (-0 .75, 2.42), ( -0 .5, 2.09), (-0 .25,
1.82),
0.723) ,
(O.OO , 1.57) ,
(1.00,0.00)
(0.25, 1.32), (0 .5, 1.05) , (0.75,
Skew_weather = GRAPH{Rand)
(O.OO , 0.00), (1.01, 0.00261) , (2.02, 0 .00522),
0 .00783), (4.04, 0.0104), (5 .05 , 0 .013), (6.06,
(3 .03,
0.0172),
0 .0323),
0.0465),
(7 . 07 , 0 .0222),
(10.1, 0.0374) ,
(13.1, 0 .0508),
(8.08 , 0 .0273) , (9 .09,
(11.1 , 0 .0423),
(14.1, 0 .055) ,
(12.1,
(15 .2, 0.0593),
(16 .2, 0 .0635),
0.0758), (20 .2,
(17.2, 0.0676),
0 .0798), (21.2,
(18.2, 0.0717),
0 .0839), (22.2,
(19 .2,
0 .0883), (23.2, 0.0932), (24.2, 0.098), (25.3, 0 .103),
(26 .3, 0.108), (27 .3 , 0 .113), (28.3, 0.118), (29 .3,
0 .123), (30.3, 0 .129), (31.3 , 0 .134), (32.3, 0.14),
(33 .3 , 0.145), (34 .3, 0 .151), (35 .4, 0.157), (36.4,
0 .163), (37.4, 0.168), (38.4, 0 .174), (39.4, 0.181),
(40.4, 0 .188), (41.4, 0 .195), (42 .4, 0.202), {43 .4,