Evapotranspiration in Hong Kong — RamAGE 
87 
measured P.E. and P.E. calculated by the 
Thornthwaite, Penman, and new formulae. 
In addition, Table 3 compares the formulae 
for the three months following the five-year 
period. Again the new formula best approxi- 
mates Hong Kong measurements. 
CONCLUSIONS 
Evapotranspiration formulae based on mid- 
latitude data should not be uncritically used 
in estimating P.E. for monsoonal or tropical 
maritime regions. 
In such regions, humidity and wind may be 
as important parameters as temperature, and 
simple formulae similar to that derived for 
Hong Kong might fairly be used to calculate 
potential evapotranspiration. 
REFERENCES 
Garnier, B. J. 1954. Measuring potential 
evapotranspiration in Nigeria. Johns Hop- 
kins Univ., Pub. Climatol. 7(1): 140-176. 
Leeper, G. W. 1950. Thornthwaite’s climatic 
formula. Austral. Inst. Agr. Sd. Jour. 16(1): 
2 - 6 . 
Penman, H. L. 1948. Natural evaporation 
from open water, bare soil and grass. Roy. 
Soc. London, Proc. Ser. A. 193: 120-145. 
1950. Evaporation over the British 
Isles. Roy. Met. Soe., Quart. Jour. 16: 372- 
383. 
Ramage, C. S. 1953. Evapotranspiration 
measurements made in Hong Kong. First 
report— October 1951 to May 1953. Roy. 
Observ. Hong Kong, Tech. Note 1 : 1-4. 
Smith, G. W. 1954. Evapotranspiration in 
Trinidad, B.W.I. Johns Hopkins Univ. Pub. 
Climatol. 7(1): 125-139. 
Thornthwaite, C. W. 1948. An approach 
toward a rational classification of climate. 
Geog. Rep. 38: 55-94. 
