A Study on Shading Effect of Solar Radiation by Vegetation

本研究的目的是通过数值求解植被内的辐射传输方程来证明研究植被对太阳辐射的遮蔽效应的可能性，而不像传统方法那样测量植被的遮蔽效应。植被内的辐射传输模型是估算植被遮蔽效应的必要条件。Ross提出的植被内辐射传输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，并对该模型存在的问题进行了思考。通过将Ross模型的数值计算结果与实测结果进行比较，验证了Ross模型的可靠性。实践证明，该模型具有一定的实用价值。导出了Ross模型的近似解。证明了扩散近似对植被内三维辐射场的适用性。分析了墙外植被对入射太阳辐射的影响。结果表明，在不测量植被内太阳辐射的情况下，通过求解Ross提出的植被内辐射传输模型，可以对植被对入射太阳辐射的遮挡作用进行数值估算。

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.