Abstract: Based on the data collected by the automatic weather station and the eddy correlation system from the urban and suburban areas in Hefei from 5 May to 10 October, 2013, differences in the urban and suburban areas are quantitatively analyzed from three aspects: meteorological factors, urban heat island(UHI) intensity, and surface energy balance. The result shows: ① UHI in the evening is stronger than that in the daytime, but not obvious in the daytime. The order of intensity of UHI in four seasons at night is winter> autumn> spring> summer. The average value of UHI intensity at night reached the maximum of 1.97℃ on clear winter nights, and the minimum of 0.76℃ was reached on clear summer nights. ② The sensible heat flux played a major role in urban energy budget, while the latent heat flux played a major role in suburban energy budgets. The daily average time of unstable stratification in urban sites is 2.3 h longer than that in suburban areas. The Bowen ratio of the four seasons in the urban area fluctuated greatly, reaching the maximum of 8.66 on sunny days in winter, and the minimum of 0.95 on sunny days in autumn. The order of the Bowen ratio of four seasons in the urban area is winter > spring> summer> autumn. The Bowen ratio in the suburban area had less fluctuations in four seasons with the maximum being 1.65 on sunny days in winter and the minimum being 0.49 on sunny days in autumn.

Key words: urbanization, urban heat island, surface energy balance, meteorological elements