Estimation Model for Spatial Distribution of Solar Radiation over Complex Terrains using 250-m Grid Size Data

Abstract

Using the elevation data, which was offered by the National Land Numerical Information with 250-m grid size, an estimation model was proposed for the evaluation of radiation conditions as a potential income of solar energy.
The main subjects of the present study are verifications of the proposed model, and clarifications of the influence of solar radiation income on the theramal environment and on the location of agricultural land use.
The results were summarized as follows:
The estimation by the grid size of 250-m feasibly represents the solar radiation conditions over complex terrains. However, in case of complex terrains which is tangled with valley and ridge, there is not enough of estimation by the grid size of 250-m. The estimation by the grid size of 1-km tends to overestimate solar radiation on a slope compared with the estimation by the grid size of 250-m.
There is a linear relation between the surface temperature and the solar radiation flux estimated with 250-m grid size over forest area.
Especially in the typical mountainous regions, farms are located just around the area of the high-insolation-condition, which is defined by the model as the most comfortable environment.