Regional Distribution of Surface Heat and Radiation Balance Components over South Ningxia Using Remote Sensing Technique

The regional land surface heat and radiation balance components are very important and not easy to deal with. To study the components of surface radiation balance and heat balance over inhomogeneous landscape, the utilization of satellite remote sensing is indispensable. In this study, a parameterization method based on Landsat-7 ETM+ data and 20 weather stations data is described to obtain the regional distributions of the components of surface radiation balance and surface heat balance over the south Ningxia area. The south Ningxia area is divided into five surface types:water surface, naked surface, half-naked surface area, grass area and forest area. The regional distributions of the components of surface radiation balance and surface heat balance are calculated and discussed according to each type. Further more, each distribution map and straight-bar figure of the components of surface radiation balance and surface heat balance is given. The results indicate that all the regional distributions are characterized by their terrain nature and the regional distributions are obvious. The figures of the mountains and rivers are very clear, it is because there is a great deal of vegetation over the mountains and rivers edge. It is seen that the derived regional distributions of surface radiation balance and surface heat balance components for the whole mesoscale area are in good accordance with the land surface status. The surface absorbed shortwave radiation is high over Liupan Mountain and Guanmen Mountain, and Yueliang Mountain and the rivers edge is high too, the minimum is in the naked area. In clear day, the surface absorbed shortwave radiation is mainly determined by surface reflectivity. The regional distribution of net radiation is similar to the surface absorbed shortwave distribution. The maximum latent heat flux is at Liupan Mountain which is second by Guanmen Mountain, Yueliang Mountain, rivers edge and other irrigated areas, the low latent heat flux areas are over naked areas.The regional distributions of surface sensible heat flux are opposite to latent heat flux.Soil heat flux is a small quantity in the heat balance function.