A Study of Penman-Monteith Model to Estimate Transpiration from Crops
Kang Shaozhong Xibng Yunzhang Liu Xiaomin (Department of water Conservancy and Architectural Engineering)
This paper deals with the deducing process of Penman-Monteith and also analyses four factors causing errors in calculations. The values of parameters in the model arc discussed , and also, a comparison is made of difference of calculated values with and without taking air pressure calibration into account and air layer stable calibration. The results show that the calculated values without taking air pressure into account are 10% -20% smaller than the actual, measured ones, while air-layer stable calibration has less significant effect upon the calculated results than those by air pressure calibration.