NCEP-NCAR Reanalysis 1

The global NCEP/NCAR reanalysis data of monthly SLP, zonal and meridional winds at 850 hPa (UV850) and geopotential height field at 500 hPa (H500) from November 1984 to February 2018 are used to discuss the high-frequency correlation between visibility and atmospheric circulation index as well as meteorological parameters.Moreover, the daily SLP, vertical velocity (Ω), RH, H500 and surface temperature (Ts) are used to discuss the differences between the regional haze days and the regional clean days in FWP.