Influence of Beijing urbanization on the characteristics of atmospheric boundary layer

Xu, Y., S. Liu, F. Hu, N. Ma, Y. Wang, Y. Shi, and H. Jia

Published in Chinese Journal of Atmospheric Sciences (in Chinese), 2009

The situation of wind speed and temperature is analyzed by utilizing the observational meteorology data from the Beijing 325-m meteorology tower of the Institute of Atmospheric Physic of Chinese Academy of Sciences. The analysis indicates that the relative wind speed is in decrease, and at lower levels the decrease is even more apparent. The vertical increasing rate of wind speed, calculated by making a linear fitting of the wind speed profile, shows an increase trend at both the lower levels under 100 m and the levels above. The vertical decreasing rate of temperature, which is generated from the temperature profile, is in increase over those years, indicating the urbanization influence on the thermodynamic structure of boundary layer. By utilizing the wind speed profile in a nearly neutral stratification, the aerodynamic parameters of the boundary layer are calculated based on the Monin-Obukhov similarity theory, showing an apparent increasing trend of the roughness length and zero-plane displacement. The analysis also shows that the relationship between friction wind speed and average wind speed is linear, and the increasing trend of friction wind speed with the average wind speed increases becomes more and more apparent. The results of this paper can be referenced by the researches of urbanization and urban environment, and can also provide potential parameterization for the boundary layer model as well as the regional climate model.