Comparison Of Different Radiation Estimation Models And Their Influence On APSIM Model Simulation Results

Daily solar radiation is a very important parameter in earth science,agriculture science, and other fields.However, compared with the conventional meteorological observatory, there were few observatories of the global radiation. Therefore,the estimation of solar radiation had become a focus. Five representative models, such as Angstrom-Prescott model,Ogelman model, Bahel model, the comprehensive model of sunshine duration anddiurnal temperature range,and Liu's model (named model ? to ?),were used to estimate solar radiation in this paper, under the analysis and comparison previous solar radiation estimation models. Daily observation solarradiation data (from 2001 to 2010) of six representative stations in Northern China Plain were used to comparethe effect of five models,according to the whole analysis period (about 10 years), In summary, five models could be used to estimate the daily solar radiation in Northern China Plain, and model ? (the comprehensive model of sunshine duration and diurnal temperature range) showed the highest accuracy.Radiation as a necessary parameter for the crop model, currently in the absence of radiation observation area using crop models,radiation parameters are based on the radiation model to obtain. In order to study the possible effects of different radiation estimation models on crop model simulation, this paper took the APSIM model to simulate the maize crop in North China as an example. After the APSIM model was calibrated, can be well simulated maize growth process and yield in the study area, Taking three typical maize crop land sites in North China (Juxian station in Shandong province, Zhengzhou and Nanyang stations in Henan province) as the research objects, were investigated the effects of radiation models on crop yield simulation. Five radiation models: the Angstrom-Prescott model, Ogelman model, the Bahel model, the comprehensive model of sunshine duration and diurnal temperature range model (referred to as the comprehensive model) and Liu's model (followed by simulation scheme 1-5) were used to simulate the total solar radiation and validated against measurement (simulation scheme 0).The radiation results of the five models were further utilized to drive APSIM model to simulate the maize yield. The results showed that different radiation estimation models had significantly different effect on the APSIM model yield simulation results, scheme 4 rendered the best result, The radiation errors brought by the five radiation models had enlarged the final results of maize yield simulated by APSIM model. The propagation error transferred to APSIM maize model simulation yield was 2.23, 2.28, 1.63, 1.85, 1.90 for the Angstrom-Prescott model, the Ogelman model, the Bahel model, the comprehensive model and the Liu's model respectively. It is obvious that the selection of the radiation model and the empirical coefficient of the radiation model should be given full consideration; with regard to the errors of crop yield simulation caused by radiation models two factors should be taken into account: the errors of the five radiation models and these errors transmitted to the crop model with augmentation. Generally speaking, Scheme 4 has the smallest error compared with other schemes. Therefore it is recommended to be used to drive APSIM model in the absence of field measurement of radiation.