Based On Dem Rugged Terrain Of The Scattered Radiation Calculation Method

Attempt to calculate the diffuse irradiation on the actual terra by used of the modern geo-information technology and the high resolution Digital Elevation Model, we focused on 3 points in discussion:1. To construct an appropriate model to describe the anisotropic character of the diffuse-radiation. According to the circle-sun suppose, we decomposed it into 2 parts, one is the isotopic part and the other is anisotropic. A ratio allocates them. Then integral the whole visible vault of heaven to get the amount of diffuse radiation at one moment. Next, integral again from the sun-rise time to down, it is the one whole day diffuse radiation amount.2. Study the landform effects on the diffuse irradiation. When integralling the visible vault of heaven, it is necessary to estimate the shadow status on every direction in 2 circle. The slope and aspect are also effective. In isotropic model, the aspect is unimportant and the diffuse radiation is reducing with the slope's increase. While the anisotropic model showed differently. The max diffuse irradiation is on the South aspect and the min on the North. On the South aspect, the diffuse radiation is increased with the slope's going up while the North is reversed. In winter, the sun high is low, the landform effect seriously, while summer is opposition.3. The compute technology based on the high resolution DEM. We used 1km 1km DEM and PCI-geomatica software to deal with the multitudinous geo-information data, and evaluated every grid point landform shadow status. The results showed the landform well.In summaries, we use two parts, isotropic and anisotropic, to describe the anisotropic diffuse-radiation; Connected the horizontal diffuse-radiation and the land modulus to calculate the diffuse irradiation on actual terra; And modem geo-tech, DEM and PCI-geomatica software and so on, is convenient and helpful to deal withmass geo-data and geo-information.At the end of the paper, the distributing map of anisotropic diffuse-radiation on actual terra in China area are given.