Penman-Monteith模型中主要参数推求及应用简化

Calculations and Predigestion of the Main Parameters in Penman-Monteith Model

通过数学分析得出修正后的Penman-Monteith模型中公式计算结果的准确性与消光系数k、叶面积指数LAI测量的准确性无关,k和LAI对于蒸腾速率的影响体现在林冠截留净辐射Rnl中;利用茎流计测量结果推算得出的冠层整体气孔阻力rst可以较好地模拟植物蒸腾,此时,rst的推算值中包含了Penman-Monteith模型所有其他参数值在测量或求解时产生的误差,同时它也是对其他参数误差的一个修正,对rst计算回归的准确性是影响模型计算结果准确性的最重要的因子。

The value of extinction coefficient（k） and leaf area index（LAI） was proved to have no effects on the result of corrected Penman-Monteith model by mathematic methods.The influence of K and LAI on evaporation speed was embodied in the canopy intercepted net radia-tion（Rnl）.Canopy integral stomatic resistance（rst） calculated by the results of sap flow meter could be used for transpiration simulating.Inaddition,it contained all the errors of other parameters and was seen as an modification for these errors.Therefore,it’s the most important pa-rameter for the accuracy of Penman-Monteith model.