Summer Urban Climate Trends and Environmental Effect in the Beijing Area

Abstract

The summer conventional meteorological data in Beijing over the past 10 years are analyzed. The results reveal that the impact of urbanization on the urban climate has become more and more apparent. (1) Over the past 10 years, the relative humidity decreased year by year and the average value in urban area was smaller than that in rural area. (2) The summer precipitation in Beijing decreased gradually in the past 10 years, especially after the year of 1998. (3) The average daily evaporation and the sunshine duration in the urban area were more than those in rural area. (4) The visibility in urban area was smaller than that in the rural area, but they all have been becoming more and more better after 1999. (5) The soil temperature also had the characteristics of UHI. (6) The number of days with the air temperature higher than 35°C increased year by year. (7) Combined with the observational data from the 325m high tower in IAP, the results also show that the inversion in urban boundary layer is very favorable to the formation of the strong summer UHI.