A Study on Shading Effect of Solar Radiation by Vegetation

本研究的目的是证明通过数值求解植被内的辐射传递方程来研究植被对太阳辐射遮阳效应的可能性，而无需像传统方法那样测量植被的遮阳效应。要估计植被遮阳效应，需要一个可靠性较高的植被内部辐射传输模型。Ross提出的植被内部辐射传递模型是其中最优秀的模型之一。本研究对Ross的模型进行了检验，并考虑了其存在的问题。通过模型数值结果与实测结果的比较，验证了Ross’es模型的可靠性。结果表明，该模型具有较好的实际应用价值。导出了Ross’es模型的近似解。证明了扩散近似法适用于植被内的三维辐射场。分析了墙外植被对太阳入射辐射的影响。结果表明，在不测量植被内太阳辐射的情况下，通过求解Ross的植被内辐射传输模型，可以对植被遮挡入射太阳辐射进行数值估计。

The objective of this research is to demonstrate the possibility of investigating a shading effect of solar radiation by vegetation by solving numerically a radiation transfer equation within vegetation, without measuring the shading effect of vegetation as it was done conventionally. A radiation transfer model within vegetation which is high in reliablitity is necessary to estimate the shading effect of vegetation. The radiation transfer model within vegetation by Ross is one of the most excellent. The examination of Ross'es model was done and its problems were considered in this research. The reliability of the Ross'es model was examined by comparison between the numerical results of the model and the measurement. It was proved that the model is able to be applied to practical use. The approximation solution of the Ross'es model was derived. The diffusion approximation was proved to be applicable to a three dimensional radiation filed within vegetation. It was investigated analytically how the incident solar radiation was decreased by the vegetation which was located outside a wall. It was demonstrated that the numerical estimation of shading the incident solar radiation by vegetation is possible by solving the radiation transfer model within vegetation by Ross, without the measurement of solar radiation within vegetation.