Effect of weakened diurnal evolution of atmospheric boundary layer to air pollution over eastern China associated to aerosol, cloud – ABL feedback

摘要: Abstract Upon the effect of atmospheric stability on air pollution, this study highlights weakened diurnal evolution boundary layer (ABL), which is crucial to formation regional fog-haze and pollution episodes over eastern China (ECN). The decrease visibility (Vis) during 1973–2012 found be related more stable ABL with that characterized by a concurrent weakening surface wind, in height, reduction temperature range (DTR, – 0.26 0.092 °C/10-years winter summer, respectively). With general synchronous variation, increase both aerosol loading cloud cover might work concert reduce solar radiation reaching surface, stabilize weaken evolution, thereby turbulent mixing pollutants enhancing pollution. This conjecture “aerosol, pollution” feedback, particular emphasis (in addition aerosol) supported our analysis 40 years trends cloud, Vis DTR from observation, optical depth MODIS, validated MERRA-2 reanalysis aerosol, height (by observation routine radiosonde sounding). Regarding linkage between ABL, result emphasizes persistent high relative humidity (RH), important must carefully considered future study. Therefore, chain processes suggested interpret occurrence ECN. First, polluted day, because radiative effects, RH can persist throughout consequently, favoring accumulation as well secondary hygroscopic growth aerosol. Second, maintenance such stable, humid contrast clear day when convective afternoon facilitates diffusion dilution pollutants. Third, under synoptic system, associated due described above, further strengthened, renders severe events. variation relationship also discussed.