Influence of stable layer formation on Asian dust behavior and air pollution

Results of aerosol lidar observations in the Taklimakan Desert and numerical experiments using regional atmospheric models showed that Asian dust outbreaks in the desert can be suppressed by the well-developed nocturnal inversion layer formed in the deep basin topography. After the morning inversion breakup, the dust outbreaks suddenly occurred in a broad area of the desert and then developed to an enormous dust storm extending as far as 1000 km in the direction of east and west.

Analyses of data from both coherent Doppler lidar and aerosol lidar observations performed in the Tokyo metropolitan area indicated that the vertical transport of Asian dust particles over the metropolitan area is influenced by the development and decline of stable layers formed in the lee side of the mountainous region due to its wind blocking effect and the radiational cooling. Also, the strong capping inversion can be formed between the Asian dust layer and the planetary boundary layer over the metropolitan area, resulting in higher concentration of non-dust aerosol particles (presumably anthropogenic particles) near the ground surface.

Thus, the stability in the lower troposphere is an extremely important factor in the regional-scale dust transport and dust outbreaks.