Abstract:

Based on the meteorological data at 3 national weather stations from 1972 to 2011 and air temperature data from 36 automatic weather stations in 2011 in Yangquan, the annual, seasonal, monthly and daily urban heat island (UHI) intensity were analyzed. The results indicate that there is the weak heat island effect in Yangquan and the annual average UHI intensity is 0.554 ℃ during 1972 to 2011. The UHI intensity is in a significant upward trend and its increase is mainly due to the increase in summer UHI. The UHI intensity is stronger in winter and autumn and weaker in spring and summer, and the maximum and minimum appear in December and May for the monthly variation, respectively. The minimum UHI intensity appears at 12:00 for the daily variation, and the UHI intensity increases with decreasing of air temperature from the early evening to early morning, and its maximum appears in the morning when temperature drops to the lowest and decreases rapidly after sunrise. The extreme UHI intensity is 7.9 ℃ at 08:00 on January 14, 2010 during 2008 to 2011. In the warming weather, the amplitude of UHI intensity increases in Yangquan and it is easy to form the stronger UHI effect in the morning and the urban cold island effect in the afternoon. In the cooling weather, the amplitude of UHI intensity decreases. It remains the weak UHI effect when temperature changes insignificantly. The major urban development factors in Yangquan are significantly positive correlations with air temperature and the number of hazy days, so urbanization development maybe enable the urban air temperature increase. However, increasing urban green space maybe reduce the UHI effect under the condition of the present economic development in Yangquan.

Key words:  Urbanization development, Heat island effect, The number of haze day