82 
PACIFIC SCIENCE, Vol. XIII, January 1959 
TABLE 1 
Monthly Potential Evapotranspiration and Meteorological Observations made at King’s Park 
(22°19'N., 114°10'E., 213 FT. above m.s.l.) and AT Royal Observatory (22°18'N., 114°10'E., 
109 FT. ABOVE M.S.L.) FOR THE FIVE-YEAR PERIOD, OCTOBER 195 1-SePTEMBER 1956, 
AND ALSO FOR OCTOBER 1956-DeCEMBER 1956 
YEAR 
JAN. 
FEB. 
MAR. 
APR. 
MAY 
JUN. 
JUL. 
AUG. 
SEP. 
OCT. 
NOV. 
DEC. 
1951 
144 
100 
91 
1952 
74 
79 
80 
88 
120 
95 
113 
104 
81 
139 
100 
76 
Potential 
1953 
72 
49 
73 
72 
99 
130 
133 
100 
119 
122 
93 
81 
evapotranspiration 
(King’s Park) mm. 
1954 
72 
77 
88 
80 
140 
102 
148 
147 
161 
133 
136 
83 
1955 
79 
81 
106 
107 
no 
116 
118 
101 
125 
147 
121 
87 
1956 
64 
84 
95 
131 
142 
157 
157 
124 
140 
141 
116 
78 
5-year 
MEAN 
72 
74 
88 
96 
122 
120 
134 
115 
125 
137 
no 
84 
1951 
104 
75 
15 
1952 
26 
32 
40 
183 
184 
560 
189 
376 
838 
17 
9 
24 
Rainfall 
1953 
27 
64 
135 
95 
354 
407 
138 
374 
564 
48 
41 
76 
(King’s Park) mm. 
1954 
53 
30 
58 
160 
89 
207 
147 
294 
171 
20 
133 
0 
1955 
2 
0 
61 
162 
446 
322 
546 
580 
115 
11 
49 
18 
1956 
67 
80 
7 
79 
299 
367 
170 
455 
165 
37 
34 
7 
5 -Year 
Mean 
35 
41 
60 
136 
274 
373 
238 
416 
371 
40 
61 
27 
1951 
77 
70 
64 
1952 
62 
61 
65 
72 
80 
82 
83 
81 
80 
77 
73 
61 
Mean temperature 
1953 
61 
61 
65 
66 
76 
82 
83 
83 
80 
79 
71 
64 
(King’s Park) °F. 
1954 
63 
61 
61 
71 
80 
82 
83 
83 
81 
76 
70 
61 
1955 
57 
64 
69 
72 
79 
81 
82 
82 
83 
77 
68 
66 
1956 
58 
61 
66 
75 
79 
83 
84 
82 
83 
77 
68 
62 
REPRESENTATIVENESS OF THE 
king’s park SITE 
An oil-drum evapotranspirometer (see Gar- 
nier, 1954) was installed at Kai Tak Airport 
(22°20'N., 114°12'E., 12 feet above mean sea 
level) and readings began in September, 1954. 
The tank was turfed with and surrounded by 
grass clipped to 1-2 inches and was watered 
from above. The site being in an extensive 
flat area near sea level differs considerably 
from King’s Park where the evapotranspirom- 
eter is atop a small isolated hill. 
Figure 1 shows results of the first year’s 
simultaneous readings. For this period it is 
safe to assume that the oil drum did not de- 
velop leaks. At Kai Tak, in moisture deficient 
