Climatology and Sugar Cane — CHANG 
387 
Increased radiation results in a rise of tempera- 
ture, though with a large time lag in a maritime 
climate. The temperature at Makiki (Fig. 10) 
did not start to rise until 1948. 
Increased radiation could conceivably bring 
about a change in general circulation. Went- 
worth (1949) noted that the prevailing wind 
in Honolulu shifted from northeast to east from 
1907 to the late 1930’s and veered back there- 
after. Increased frequency of east wind suggests 
a southerly location of the subtropical anti- 
cyclone, less frequent trade-wind weather, but 
not necessarily an increase in cyclonic activities; 
therefore, the trade-wind rainfall should de- 
crease when the east wind is prevalent. At 
Makiki there was a trend to decreased rainfall 
from the 1920’s to 1941 and to increased rain- 
fall thereafter (Fig. 11). This explanation of 
the rainfall trend is tentative, however, and re- 
quires further study. 
Whatever the causes for climatic change may 
be, its impact on agriculture is varied and pro- 
found. In general, the climate in Hawaii has 
become more favorable for sugar-cane culture 
during the last 20 years. This must account for 
part of the yield increase during that period. 
MODIFICATION OF CLIMATE 
The climate of Hawaii is, in general, well 
suited to the growth of sugar cane. Water econ- 
omy is the one area where the climatic environ- 
ment could be altered significantly to bring 
about a higher yield. Irrigation in the Hawaiian 
sugar industry started in 1852. At the present 
time 54% of the plantation area is irrigated. In 
Fig. 8. Solar radiation (langleys/day) in Hawaii. 
