Abstract
Synoptic-scale meteorological conditions causing the long-range transport of air pollutant with light gradient winds were investigated by analyzing the atmospheric pressures and ground-level winds as well as the aerological data for the period from May to September 1979. Special attention was paid to the thermal low which was generated in the daytime in the mountainous region, and the characteristics of the upper atmosphere.
Long-range transport occurred under a synoptic-scale high pressure with an upper wind of about half the wind speed averaged over the entire period under study. Under these conditions, local winds developed in the lower atmosphere, and the thermal low and subsidence inversion accompanied by the synoptic-scale high pressure led to the combination of the local winds into two large-scale winds blowing towards the thermal low. The synoptic-scale pressure distribution determines the location of the thermal low center and therefore also determines the horizontal extent of the long-range transport.