Preliminary look at the diurnal behavior of the PBL

Atmospheric factors that govern the dispersion and transport of air pollutants discussed include the behavior of the planetary boundary layer (PBL) during the morning hours, beginning before the sun rises; the influence of surface heating after the sun rises on erosion of the base of the nocturnal inversion; and the influence wind speed and height and temperature on mixing throughout the boundary layer. It is pointed out that many of the processes occurring within the PBL must be parameterized in numerical models rather than being directly calculated since they occur on scales smaller than the resolution of the models