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

植物冠层的热量和温度是植物生长、热量收支和遥感的重要因子。本研究的目的是弄清植物冠层的热储存或植物温度的有关问题。第一个课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个模型的比较，第三部分是观测叶温与模型的比较。行植冠层下土壤热通量在不同部位有较大差异。在行间观测到的土壤热通量可能是冠层下平均值的2倍。第二部分，分别用热收支方程梯度法模型、植物冠层单层模型和简化的多层模型估算了热储量。结果表明，单层模型计算方法简单，但计算结果较好。第一个模型显示在每个观察时间内的大变化。第三，虽然蒸发效率和整体输送系数难以确定，但利用经验参数，用单层模型估算了实测叶温。多层模型计算的叶温偏小。这似乎是由于田间的行植冠层与均匀冠层在理论上的不同，改变了太阳辐射在冠层中的传输方式。

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.