Grey assessment and prediction of the urban heat island effect in city

The grey-system theory was introduced into the assessment and prediction of the urban heat island effect of a city. The contribution level of the factors influencing the urban heat island effect of Xi'an city was analyzed by the grey relativity analysis method. The results show that the artificial heat release is the main factor for the formation of the urban heat island effect of Xi'an city, while the wind velocity, hours of sunshine, and relative humidity are the main meteorological factors affecting the urban heat island effect of Xi'an city. The prediction results of the system cloud grey model (SCGM) accord well with the actual condition of Xi'an city. It is indicated that there has been increasing trend of the urban heat island effect in Xi'an city and shows that SCGM model has great advantages for multifactor correlative system prediction.