植被温度预测模型的分析与确定

Analysis and Determination of Vegetation Temperature Prediction Model

为研究植被热湿传递模型并预测植被叶片表面温度,从能量守恒角度出发,建立绿色植被传热传质多层模型和单层模型,得到了模型中各动力阻抗的表达式,通过对两种节点模型进行理论求解和回归分析,分别给出多层模型和单层模型叶片温度的表达式。对10种校园常见绿化植物树叶表面温度等参数进行测试,并将试验结果与模型预测结果进行对比分析。研究结果表明:随着参考高度空气温度、参考高度空气相对湿度、叶片宽度、叶面积指数、风速和太阳辐射强度的单因素变化,单层模型与多层模型预测的温差(即植被叶片温度与参考高度空气温度之差)的变化趋势相同,但是单层模型未考虑植被冠层与土壤二者间的热湿交换特性,其预测的温差变化幅度小于多层模型;在某些条件下,单层模型与多层模型预测温差非常接近;模型预测温差与试验结果吻合良好,短时间内植物的叶片温度主要受太阳辐射强度和风速的影响;太阳辐射强度为中等时,单层模型的预测温差比多层模型预测温差的误差小,太阳辐射强度过高或过低时多层模型预测温差比单层模型预测温差的误差小。

In order to study the heat and moisture transfer model of vegetation and predict the surface temperature of vegetation leaves,a multi-layer model and a single-layer model for heat and moisture transfer of green vegetation were established from the point of energy conservation.The expressions of dynamic impedance in the model were clarified.Through theoretical solution and regression analysis of the two nodal models,the leaf surface temperature expressions of multi-layer model and single-layer model were given respectively.The leaf surface temperature and other parameters of ten common campus greening plants were tested,and the experimental results were compared with the predicted results of the two models.The results show that with the single factor changes of ambient air temperature,relative humidity of ambient air,leaf width,leaf area index,wind speed and solar radiation intensity,the variation trend of temperature difference predicted by single-layer model and multi-layer model(that is,the difference between vegetation leaf temperature and reference height air temperature)is the same,but the single-layer model does not consider the characteristics of heat and moisture exchange between vegetation canopy and soil,and its predicted temperature difference range is smaller than that of multi-layer model.In some conditions,the single-layer model and multi-layer model predicted temperature differences are very close.The temperature difference predicted by the model is in good agreement with the experimental results.In a short time,the leaf temperature of plants is mainly affected by the solar radiation intensity and wind speed.When the solar radiation intensity is medium,the error of single-layer model is smaller than that of multi-layer model.When the solar radiation intensity is too high or too low,the error of multi-layer model is smaller than that of single-layer model.