Research On The Spatiotemporal Dynamic Distribution Of Solar Radiation And The Future Trend Of Solar Radiation

The proposal of the"dual carbon"policy has transformed traditional building energy conservation work from the original"energy conservation"to the dual goals of"energy conservation and carbon reduction".With the development of building ontology technology,the energy-saving potential of building ontology has reached the limit.Therefore,building energy efficiency and carbon reduction work must be transformed to renewable energy applications.Solar energy technology has become one of the most widely used renewable energy technologies in recent years due to the technologies are mature and application costs are low.Solar radiation is an important parameter affecting the efficient utilization of solar energy in buildings,and its spatiotemporal dynamic variation is of great significance to the planning,deployment and design of renewable energy utilization technology.In recent years,due to the influence of environmental pollution,climate change and other factors,the decadal variation of solar radiation is drastic,showing a significant dynamic change.At the same time,China has a large land area,affected by latitude,terrain and other factors,the spatial distribution of solar radiation is very different.The high cost of the observation of solar radiation data for whole station leads to the serious loss of solar radiation data.The existing studies on the spatiotemporal dynamic distribution of solar radiation mainly focus on local case studies.Due to the complex climatic conditions and vast geographical area in China,case studies in local areas are difficult to guide other regions,and the research results are severely limited.Based on this,the whole-process estimation system of solar radiation is developed by using the existing estimation models of global solar radiation and diffusse solar radiation.On this basis,the interdecadal variation law of global solar radiation and diffuse solar radiation is studied by innovative trend analysis method,and the spatial distribution of time variation rate of global solar radiation and diffuse solar radiation is obtained.M-K mutation test is used to determine the mutation of global solar radiation and diffuse solar radiation,determine the effective prediction time of future solar radiation,and obtain the spatial distribution of solar radiation in the future 5 to 10 years.The main conclusions are as follows:（1）The traditional empirical model of steady-state solar radiation estimation has the problems of low prediction accuracy and large error.In this study,the traditional steady-state solar radiation estimation empirical model is modified into a dynamic solar radiation estimation empirical model by introducing astronomical factors,and the traditional model is compared.The results show that the coefficient of determination（R²）of the revised power function model is in the range of 0.86-0.99,the root mean square error（RMSE）is in the range of 0.018-2.62,and the R² and RMSE are increased by 0.49%and 6.44%（2）The decadal variation of solar radiation is dramatic and the trend is complex,but the traditional trend analysis method identifies a single trend.This study uses innovative trend analysis to identify the spatio-temporal dynamic distribution of global solar radiation and diffuse solar radiation.The results show that:in terms of the annual solar radiation variation law,the global solar radiation in China presents a decreasing change law on the whole,and the average annual global solar radiation change rate is-4.26MJ/m²/y.The average rate of change of the annual diffuse solar radiation is 0.34 MJ/m²/y.As for the seasonal variation of solar radiation,the global solar radiation in spring showed an upward trend,and the average variation rate was 0.89 MJ/m²/y.The variation of global solar radiation in summer,autumn and winter showed a decreasing trend.As for the seasonal variation trend of diffuse solar radiation,the diffuse solar radiation in spring and autumn showed an upward trend,and the average rate of change was 0.17 MJ/m²/y and0.067 MJ/m²/y,while the diffuse solar radiation in summer and winter showed a downward trend,and the average rate of change was-0.022 MJ/m²/y and-0.066 MJ/m²/y.（3）The abrupt change of the time variation of solar radiation is prominent,and it is difficult to predict the future solar radiation change with large error and low precision.In this study,M-K test was used to determine the abrupt time point,effective prediction duration and effective prediction data of solar radiation change,and the spatial distribution of future solar radiation for future 5 and 10 years was obtained.The results show that the annual global solar radiation value of China in the future 5 years and 10years ranges from 3020 to 6840 MJm^-2 to 2970 to 6940 MJm^-2 respectively.Compared with the historical distribution of global solar radiation,the average change of global solar radiation will decrease by 5.3%in the future 10 years,and it will decrease significantly in Tibet,Qinghai and Inner Mongolia,etc.,which will still be a high-value area of solar energy resources in China in the future,with greater utilization potential.The annual diffuse solar radiation values ranged from 650 to 3100 MJm^-2,680 to 3120 MJm^-2,respectively,and the diffuse solar radiation showed an increasing trend from north to south.Compared with the historical diffuse solar radiation distribution,the average change of diffuse solar radiation in the future 10 years will increase gradualy,especially in Yunnan,Guangxi and the southern coastal areas,the annual diffuse solar radiation increase trend is obvious,and the average change of diffuse solar radiation increases by2.3%.