The Characteristics And Simulation Of Energy Balance And Micrometeorological Variables And Surface Radiation

Microclimate is the ambient of plant and energy balance drives the circulation of matter. At present, there are many relative models, in which processes considered were complex. But the detailed tests of experiments on various processes were trailed the development of models. The main work of this paper was combining the comparative detail measurement with model analysis, which is benefit to the development and use of the models and the management of agriculture.The variation of microclimate factors (air temperature, relative humidity and wind speed), energy budget, canopy and soil temperatures were analyzed in this paper. The, using the measured meteorological data in Yucheng, the SHAW (the simultaneous Heat and Water) model was used to simulate the following factors: microclimate variables, energy balance, canopy and soil temperature, and surface radiation.The simulation indicated:All of them have obvious variations, which were influenced by the resistance of canopy, development of the maize and alternation of day and night.Air temperature, relative humidity and wind speed above the 2/3 height of plant were simulated better than the low layers.The model simulated energy balance well since the model efficiency of net radiation reached 0.97, and latent heat 0.81, sensible heat 0.78, while the simulated latent heat flux was higher and the sensible heat flux was lower. The ground heat flux was not simulated very well. In addition, the analysis found that precipitation influenced the measurement greatly.The canopy temperature was simulated well above 2/3 of plant height, which was according to the simulation of air temperature. Soil temperature was simulated reasonably besides 2cm depth.SHAW model well simulated the short and long wave radiation reflected by the canopy, while the sky long-wave radiation was not simulated so well. Then the empirical schemes were employed, and the improvement was obvious.In conclusion, SHAW model simulated the factors above reasonably and reliably. Some weaknesses discovered can be the references of the improvement of the SHAW model and the development of other models.