STUDIES ON HEAT STORAGE OF PLANT CANOPY DUE TO THE VARIABILITY OF AIR AND SOIL TEMPERATURES.

植物冠层的储热和温度是植物生长、热收支和遥感的重要因子。本研究的目的在于阐明植物冠层蓄热或植物温度的一些问题。第一个主题是植物冠层下土壤热通量的影响。第二部分是植物温度与几种模型的比较，第三部分是叶片温度观测与模型的比较。关于第一个主题，得到了以下结果。在行植物冠层下，不同位置的土壤热通量差异较大。行间空间观测到的土壤热通量可能是林冠下平均值的2倍。由于这种差异是系统存在的，在热收支分析中不可忽视。其次，采用以下三种模型对储热量进行估算；模型采用热收支方程和梯度法，植物冠层单层模型和简化的多层模型。结果表明，单层模型计算方法简单，但效果较好。第一个模型显示了在每个观测时间内的大变化。最后一种模型存在计算复杂的缺点。第三，在蒸发效率和体积传递系数难以确定的情况下，利用经验参数对观测叶温进行单层模型估计。多层模型得到的叶片温度比实际观测值要小。从理论上看，由于田间行状植物冠层与均匀冠层的差异，改变了太阳辐射在冠层内的透射模式。

Heat storage and temperature of plant canopy is an important factor for plant growth, heat budget and remote sensing. The purpose of this research is to make clear some subjects with respect to the heat storage of plant canopy or temperature of plant. The first subject is the influence of soil heat flux under plant canopy. The second one is the comparison of plant temperature with a few models and the third one is the comparison of the observed leaf temperature with model.About the first subject, the following result was obtained. Under row plant canopy, there are large differences of the soil heat fluxes according to the positions. The soil heat flux observed in the interrow space may be two fold of the mean value under canopy. As the difference occurs systematically, it is not able to neglect in the analysis of heat budget.On the second, the estimation of the heat storage was tried by the following three models ; model using heat budget equation and gradient method, one layr model of plant canopy and a simplified multi-layr model. As the results, the one layr model was good in spite of the simple calculation method. The first model showed the large variation in every observed time. The last model has shortcomings of complicated calculation.On the third, observed leaf temperature was estimated by one layr model using the empirical parameters although it is difficult to identify the evaporation efficiency and the bulk transfer coefficient. Leaf temperatures obtained by multi-layr model were smaller than the observed one. It seems that the difference between the row plant canopy of the field and the uniform canopy in the theory chages the patterns of transmission of solar radiation in the canopy.