Abstract. The study and control of air pollution need to detect the structure of atmospheric boundary layer (ABL) in order to understand the mechanism of interaction between atmospheric boundary layer and air pollution. However, when extreme pollution occurs, the detection of atmospheric boundary layer structure is very scarce. Beijing, the capital of China, has experienced a severe haze pollution in December 2016. The city issued its first red air pollution warning of this year (the highest PM2.5 concentration was later monitored to exceed 450 μg m−3). In this paper, the vertical profiles of wind, temperature, humidity and extinction coefficient (reflecting aerosol concentration), as well as ABL heights and turbulence quantities under heavy haze pollution are analyzed, with collected data from Lidar, wind profile radar (WPR), radiosonde, 325-meter meteorological tower (equipped with 7-layer supersonic anemometer and 15-layer low frequency wind, temperature and humidity sensors) and some other ground observations. ABL heights obtained by three different methods based on Lidar extinction coefficient data (Hc) are compared with the heights calculated from radiosonde temperature data (Hθ) and from WPR wind speed data (Hu). The results show that increase of water vapor has greatly promoted the hygroscopic growth of aerosols, the corresponding extinction coefficients also increased significantly. The PBL heights Hθ and Hu of heavy haze pollution day were generally lower than those of clean day, but Hc increased. Turbulent activities were great inhibited during haze pollution, time changes of both friction velocity (u*) and turbulent kinetic energy (TKE) have obvious inverse correlation with that of PM2.5. The results of this paper could provide some reference for the parameterization of the boundary layer height and turbulent diffusion process in the numerical model of severe air pollution.
Integrated System for Atmospheric Boundary Layer Height Estimation (ISABLE) using a ceilometer and microwave radiometer
