Study On Temporal And Spatial Distribution Of Radiation Resource Based On GIS In Karst Mountain Area

Spatial distribution is one of the most important Climate resources, is the main energy of all natural phenomena on earth, playing a decisive role in the formation of weather and climate.Percentage of sunshine, sunshine duration and solar radiation are the three important indicators of energy resources. Among them, the solar radiation is to determine the main factors of the karst mountain climate, the spatial distribution difference will influence other climate elements distribution, to form a unique microclimate in the mountains; Sunshine duration is an important index of solar radiation on the time scale; the sunshine percentage is the important factor of solar radiation, is indispensable to build solar radiation estimation model. As one of the important agricultural climate resources, the temporal and spatial distribution of radiation resources has a direct impact on crop photosynthesis, having important influence agricultural products quality and production to the agricultural industry layout, etc. At the same time, the research for the development and utilization of the mountainous climatic resources promoting the karst mountain area of agriculture and forestry reasonable planning and development, has a certain guiding significance.On the basis of existing research, using GIS technology and the DEM data and MODIS remote sensing image, comprehensive consideration of astronomical factors, atmospheric factors and topographic factors on the influence of time and space distribution of radiation energy resources, setting up different energy resources calculation model, for radiation energy resources for simulation of time and space in the county of bama, working out different time scales and space distribution of percentage of sunshine, sunshine duration and solar radiation, explore the typical karst mountain space-time distribution of radiation energy resources, And using the radiation energy resources data for the camellia oleifera planting climate suitability evaluation results are modified and optimized in bama county.The main contents and conclusions are:1. Adopt the method of strip re-sampling, to deal with MODIS06 cloud cover data,sunshine percentage by remote sensing estimation model is established, piecewise simulate the sunshine percentage by time and space distribution in bama county. By and large, the sunshine percentage are greatly influenced by mist, the overall value is low, and presents the spatial distribution characteristics of low middle, high around, and the sunshine percentage in different numerical differences.2. Sunshine duration fluctuates largely in the morning and evening in bama county and value is lower than the afternoon. Sunshine duration order from more to less according to season distribution for summer > autumn > spring > winter, Seven- September sunshine hours are at most. In the spatial distribution of the sunshine duration present a non-latitude and irregularity,and its space distribution are greatly influenced by terrain shading effect. sunshine time obviously lower than other area in karst mountains and presents the fragmentized; sunshine time on the south slope, southeast and southwest slope significantly greater than other slope direction and sunshine duration gradually reduce with the increase of slope.3. Under the influence of astronomy, atmospheric and topographic factors, Solar radiation in western mountain areas is significantly higher than other areas in bama county, greatly influenced by altitude, and broken terrain karst mountain area of solar radiation value also is low.From the point to the slope and aspect, solar radiation value on the southern slope significantly greater than the northern slope and with the increase of slope solar radiation value gradually decreases. In the solar total radiation, the proportion of solar direct radiation is larger than others,July solar radiation value maximum, minimum in December.4. By using the meteorological data of camellia oleifera planting suitability analysis can be obtained, most regional hydrothermal condition in bama county is good and Suitable differential planting. Using the radiation energy resources data, Analysis of time and space distribution of radiation energy has a great influence on the camellia planting, so should choose light conditions better for camellia oleifera planting and regional planning.