The thermodynamic structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing

Abstract. To investigate the impacts of multiscale circulations on planetary boundary layer (PBL), we have carried out PBL thermodynamic structure field experiment with a Doppler wind profile lidar, microwave radiometer, and ceilometer from January 2018 to December 2019 in Beijing. We found that direct regulatory effect synoptic circulation worked through transporting accumulating pollutants front mountains daytime, while indirect coupling mechanisms nighttime. The horizontal different-direction winds produced severe pollution convergent zone. vertical upper environmental lower regional breezes regulated mixing diffusion by generating dynamic shear advective temperature inversion. also dominating led great differences pollution. cyclonic resulted typical multilayer characterized high (600 m), inversion (900 an inhomogeneous stratification. Meanwhile, strong pushed zone south southwesterly mono-layer low (400 m) (200 m). westerly hybrid-structure PBL, was generated zonal winds. Strong severe-pollution mountains. There no distinct under anticyclone circulation. study systematically revealed appreciable effects air quality, which enriched prediction theory atmospheric complex terrain.