Using an Energy Balance
The Theory
Using the LI-6400
17-3
(17-4)
The sensible heat flux is a function of the leaf - air temperature difference, the
specific heat capacity of the air
c
P
(J mol
-1
K
-1
), and the one-sided boundary
layer conductance of the leaf
g
b
(mol m
-2
s
-1
)
(17-5)
The energy balance equation now becomes
(17-6)
If we let
, and note that for small
D
T
(17-7)
D
T
(17-8)
where
for most leaves,
W m
-2
K
-1
, and
c
P
= 28 J
mol
-1
K
-1
. While
a
and
k
can vary widely for different light sources
(Figure 17-2 on page 17-5), their product is fairly conservative (Table 17-1).
L
44100
E
=
Q
2
c
p
g
b
T
l
T
a
Ð
(
)
=
a
kR
Q
2
es
T
w
273
+
(
)
4
2
es
T
l
273
+
(
)
4
Ð
+
44100
E
2
c
p
g
b
T
l
T
a
Ð
(
)
+
=
D
T
T
l
T
a
Ð
º
T
l
273
+
(
)
4
T
a
273
+
(
)
4
4
T
a
273
+
(
)
3
D
T
+
»
D
T
a
kR
Q
2
es
T
w
273
+
(
)
4
T
a
273
+
(
)
4
Ð
44100
E
Ð
+
2
c
p
g
b
8
es
T
a
273
+
(
)
3
+
-----------------------------------------------------------------------------------------------------------------------------------
=
e
0.95
»
s
5.67
10
8
Ð
´
=
Summary of Contents for LI-6400
Page 1: ...Using the LI 6400 Portable Photosynthesis System ...
Page 15: ...Part I The Basics ...
Page 16: ......
Page 174: ...Making Measurements Answers to Questions 4 56 Using the LI 6400 4 ...
Page 175: ...Part II Useful Details ...
Page 176: ......
Page 200: ...Standard Tools Power ON Hooks 5 24 Using the LI 6400 5 ...
Page 214: ...Real Time Data Real Time Graphics 6 14 Using the LI 6400 6 ...
Page 234: ...Environmental Control Light Control 7 20 Using the LI 6400 7 ...
Page 244: ...Light Sensor Considerations Gallium Arsenide Phosphide GaAsP Sensor 8 10 Using the LI 6400 8 ...
Page 288: ...Data Logging Making Your Own AutoPrograms 9 44 Using the LI 6400 9 ...
Page 289: ...Part III Working With Files ...
Page 290: ......
Page 312: ...The LPL File System Troubleshooting 10 22 Using the LI 6400 10 ...
Page 340: ...Downloading Files Using a Data Capture Program 11 28 Using the LI 6400 11 ...
Page 375: ...Part IV Configuration Issues ...
Page 376: ......
Page 420: ...Defining User Variables Old Style vs New Style 15 18 Using the LI 6400 15 ...
Page 454: ...Using an Energy Balance Further Reading 17 12 Using the LI 6400 17 ...
Page 455: ...Part V Maintenance Troubleshooting ...
Page 456: ......
Page 572: ...Troubleshooting Useful Information 20 46 Using the LI 6400 20 ...
Page 593: ...Part VI Programming ...
Page 594: ......
Page 622: ...Programming with LPL Compiler Directives 22 28 Using the LI 6400 22 ...
Page 846: ...Index I 16 Using the LI 6400 ...