viation 
hat of 
y the 
\arized 
ns is 
tion is 
leaf 
f corn, 
large 
t each 
leaf 
sans is 
e must 
ght 
i 
15:30 
  
21.5 
=0.4 
pi 
= 17 
  
and 
par ed 
is. 
Daily 
Fig. 7. 
is and 
% on 
3% on 
.196 on 
erence 
id and 
h, and 
low. 
rature 
opy at 
3 (Fig. 
Id that 
r ratio 
an that 
is the 
, 1993 
atio of 
the 
of the 
)ybean 
nopy 
that of 
same 
age in 
e, "the 
es the 
canopy temperature for both crops at a latter 
growth stage. 
  
40 0.8 
‘92.08.30 
   
      
  
  
  
  
35 | (%Percentage of plan cover Ju radiation t 
06 = 
g 30 + grea sono) f... Soybean(83.4) E 
I i Nem X Co 
et [X5 104 © 
a 3 
E 2p = 
o A. 
+ 02 © 
o 
15H 3 
10 : - — 0.0 
0:00 6:00 12:00 18:00 24:00 
Local time(hr.) 
Fig. 7 (a) Daily changes of canopy temperature, 
airtemperature and solar radiation 
for crop fields (on August 30, 1992). 
  
50 1.0 
(R9 96 20 iá Soe radiation 
*d Percentage of plan cover a 
mu OF X jos £ 
= Sweet corn(28.4 PRE = 
Am EC > ue Sr 24 = 
= 30 = € N 0.6 5 
GS S. = 
o Me 3 
& 2} a Pos 9 
5 Ne E 
p T du: p rs © 
10d Lo Ter Ai 7702 
r temperature he o 
0 L À À L À À À L À H A À 3 3 À À À À 0.0 
  
  
  
0:00 6:00 12:00 18:00 24:00 
Local time(hr.) 
Fig. 7(b) Daily changes of canopy temperature, 
air temperature and solar radiation 
for crop fields (on June 30, 1993). 
  
  
  
  
  
40 0.8 
'93.07.24 fX ^ (9Percentage of plan cover 
35]- Solar To isi E 
o 306 = 
© 30} Soybean(49.1 = 
3 es Ty corn(81.9) S 
S asl 104 5 
a. E E 9 
5 20 }- / ess — am, - 
i? [2 see {0.2 5 
15 + d Air temperature \ Tiva 3 
EN - sU N 
1 0 bb Lk bh US iL 0.0 
0:00 6:00 12:00 18:00 24:00 
Local time(hr.) 
Fig. 7(c) Daily changes of canopy temperature, 
air temperature and solar radiation 
for crop fields (on July 24, 1993). 
3.3.2 Maximum canopy temperature: The maximum 
canopy temperature that characterizes daytime 
Canopy temperature, was analyzed in relation to 
vegetation cover ratio and growth stage. The mean 
maximum canopy temperatures for four clear days 
of each growth stage in 1992 and 1993 are shown in 
Fig. 8. In the latter growth stage of both years, the 
maximum canopy temperature of the corn field 
became lower than that of the soybean. 
In an early growth stage, however, the maximum 
canopy temperature of the corn field was higher 
than that of the soybean field or was nearly the 
same as the soybean field. There is a large 
difference in both years for the differences of 
maximum canopy temperature between the corn 
field and the soybean field. It may be caused by 
soil background temperature, which changes with 
soil moisture. 
  
  
  
  
   
  
  
  
  
  
  
  
  
60 
à dà ; 1992 
& sr - ( %s)Percentage of plant cover 
9 x 
a sor NN 
© S 
& ask 92] 3: 
5 TAX 
© L etc 
E 40 e 
3 Bio 
E st |9i— 
= = 2 (es) 51) 
$ of [512 Es 
o 
25 50 - t 
06/28-07/01  07/07-07/26  07/29-08(07  08/14—08/29 
45 
1993 
g ( 96 )Percentage of piant cover 
S 40F (17) 
S 
o s 
a ; 
E as 
2 b 
E sor |oj9 
3 © 
= z 
fon 
  
  
  
  
  
  
  
25 zm z o mp 
06/17-06/18 06/25-06/30 07/04-07/05 07/14-07/25 08/19-08/21 
Growth stage 
Fig. 8 Comparisons of the mean maximum 
canopy temperatures for each growth stage. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
40 
= 1992 
2 4 Sweet com Soybean 
D : Tes T 
e 3s3or à, 
o 3 
© * 
= A 5S 
© i 
o 20 PU 
5 ka et 
S » 
= . 
C. 107 P A A 
= A Sur a pet 2 
= E CP I em 
à A 
160 180 200 220 2:0 260 280 
(06/08) (06/28) (07/18) (08/07) (08.27) (09/16) (10/06) 
40 
£ 1993 Sweet com Soybean 
Oo -——-— —A-—— 
c L 
© 30 
D 
= 
© 
o 20r 
= À 
o t d "e. A. 
C. D A t € 
= 10 ° Sa. 
© 4. rm mg 
+. opu 3&9... Meremeremetesseauunuu ANE uM € 
0 t : - 
160 180 200 220 240 
(06/09) (06/29) (07/19) (08/08) (08/28) 
Julian days(month/day) 
Fig. 9 The variations of the maximum canopy 
temperature minus the maximum air temperature 
for the measurement period. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996 
SEGA RS AR EPS