The Air Temperature Variation and Heat Island Effect in Urban Area of Shanghai City

Based on the data set of automatic observation station,the variation characteristics of air temperature and heat island in urban area of Shanghai city are analyzed.The results show that,there are some high temperature centers in urban area of Shanghai city,located at Hongkou gymnasium,Jing'an district and Yan'anxilu road.Their air temperature are over 36℃ after noon and daily average temperatures are over 31.8℃ in summer.Temperature differences between the day and the night over these area are high over 8℃ in summer and still 2℃ in winter.It means a stable urban heating distribution.There are clear climate characteristics of daily and annual variation of air temperature in urban area and different to suburb,but small difference between each urban station.The urban heat island is affected by the temperature variation of urban area and suburb area,and made a special variation characteristic.Because the air temperature of urban area differs the suburb in variation,the urban heat island differs the air temperature in variation.Daily average urban heat island intensity over Shanghai is about 2.6℃ in summer,over 3.7℃ in spring,and under 1℃ in winter.Annual average heat island intensity is about 0.7℃.The urban heat island intensity over Shanghai is lower in the day and high in the night,and makes the highest peak in the midnight.Interannual variation of the urban heat island intensity over Shanghai is obvious,and with a rise trend over 0.05℃/a in July.