Development of the model of estimating evapotranspiration using climate data and vegetation factors.

本研究的目的是建立一个利用简单气候资料和植被因子估算蒸散量的模型。为此，作者利用波文比技术，在不同气候区、不同地点，（1）斯里兰卡，（2）泰国，（3）瑞典，（4）北海道，（5）官渡地区。通过增加风速和植被覆盖度，改进了蒸散-覆盖度的经验模型，改进了Aoki等（1993）的蒸散经验模型，并通过增加气孔导度和植被高度进一步改进。但由于资料较少，气孔导度的变异性较大，方程的解不清楚，虽然加入两个因子后，方程的解可以减小蒸散量的误差。

The aim of the research project is to develop the model of estimating evapotranspiration using simple climate data and vegetation factors.For this porpose, the authors measured actual evapotranspiration using Bowen ratio technique and micrometeorological conditions such as temeprature, relative humidity, soil moisture tension, vegetation coverage, vegetation hight and leaf stomatal conductance at different climite regions, places, and different types of vegetation as follows : (1) Sri-Lanka, (2) Thailand, (3) Sweden, (4)Hokkaido, (5) Kantho Region. By addint wind speed and vegetation coverage, the author sucesseeded to improv the epirical model of evapotrans-coverage, the autor sucsseeded to improv the empirical model of evapotranspiration made by Aoki et al. (1993).Further improvement was made by putting stomatal conductance and vegetaion height. But the equation was not clear becase of less data and valiety of stomatal conductance, although the equation showed to decrease the error of estimate evapotranspiration if two factors were added by the model.