Impact Of Urban Growth On The Heat Island In Hefei

In this paper, we studied the characteristic of the urban heat island in Hefei, according to the observed conventional data in the urban and suburb station of Hefei and the data of set ground sites. We got the correlation analysis between the urban heat island intensity in Hefei and the urbanism statistic data in Hefei, and got main factors that affect urban heat island and analyzed the reasons. The research has mainly done the below research work:1. The characteristic of urban heat island in Hefei is illustrated as fellows. The urban heat island in Hefei began in 1965. The year change character is increasing trend by 0.1℃/10 years. The season change character is that urban heat island appears in four seasons. The urban heat island intensity in winder is the most, and the average is 0.47℃. But the increasing trend is gentle, and the peak of subtraction is little in winter. The urban heat island intensity is the lowest in summer, and the average is 0.22℃. The urban heat island intensity in spring and fall is 0.33℃and 0.38℃respectively. The increasing trend is obvious in fall. In a day, the night urban heat island intensity is larger than the day. The urban heat island intensity in night and day is 1.0℃and 0.5℃respectively.2. The urbanization of Hefei is illustrated as fellows. The population Urbanization reflects that the rate of non-agriculture population is increasing by 2.6%. The economy Urbanization reflects that the rate of the per-capital GDP is increasing by 19.1%. Since 1978, the rate is exponential growth and the fitting curve equation is y = 548.2e0.1894x,R2 = 0.9546. The average rate of the total output value of the construction industry is increasing by32.6%. Since 1978, the rate is exponential growth and the fitting curve equation is y = 14511x1.6124,R2 = 0.8975.The society Urbanization reflects that the rate of urban greening is increasing by 11.9%. The lifestyle Urbanization reflects that the average rate of electricity consumption is increasing by 9.9% and the average rate of household appliances increasing by 30%.3. We made grey correlation between the urban heat island and meteorological factors in Hefei. There is significant relation between the urban heat island intensity and wind speed and relative humidity in Hefei. The correlation coefficients are 0.5109 and 0.5058 respectively. The relation between the urban heat island intensity in Hefei and wind speed is negative correlation, the equation is y = -0.0779x + 2.5865. Wind speed relief the urban heat island. The relation between the urban heat island intensity in Hefei and relative humidity is correlation, and the equation is y = 0.0011x3 - 0.236x2 + 16.879x - 400.67.4. We made grey correlation between the urban heat island and urbanization factors in Hefei. There is significant relation between the urban heat island intensity in Hefei and the rate of non-agriculture population , year-end population , area of urban greening , household appliances , per capital GDP and generated energy. The correlation coefficient is above 0.63. There is relation between the urban heat island intensity in Hefei and secondary industry, tertiary industry and industrial added value. The correlation coefficient is above 0.6. There is poor relation between the urban heat island intensity in Hefei and the gross investment of national assets, the construction industry of gross output and vehicle quantity. The correlation coefficient is down 0.6 and decreasing.5. There is significant relation between the urban heat island intensity in Hefei and the rate of non-agriculture population. The log fitting curve equation is y = 0.3011Ln(x) - 0.5716,R2 = 0.2202 through a 0.01 test of significance. There is correlation between the increasing rate of the city green area and the heat island intensity in Hefei,The relation between the urban heat island intensity in Hefei and the increasing rate of urban greening is negative correlation, but the correlation is not significant. According to the observational data on May thirty-one 2008, the daily mean temperature maximum in Wuhu Road and Huancheng Park was higher 1.0℃than in Shifuguangchang, which shows that the urban green belt has significant cooling effect. There is relation between the urban heat island intensity in Hefei and household appliances, generated energy, industrial added value and tertiary industry. The tests past the 0.01 significance test. It shows that the hefei urbanization significantly effects the urban heat island intensity.