Revisiting Observed Changes in Cloud Properties over Europe

Abstract: The Earth’s atmosphere is a vulnerable system which is easily changed by micro- and macrophysical variations. Big decreases in pollution levels of sulfur dioxide over Central Europe from 1980s to 2000s led to decreased mass concentration of atmospheric solid and liquid particles. This gives the opportunity to investigate how these particles influence the atmosphere. Newly released satellite climatology data was used to analyze statistics of cloud properties during four years in the high polluted atmosphere (1985-88) and four years in the less polluted atmosphere (2004-07). These two periods were investigated in collaboration with Atmospheric Remote Sensing Unit of the research department of the Swedish Meteorological and Hydrological Institute (SMHI). Cloud top temperature of liquid clouds over polluted regions during the earlier period was colder by more than 2 K and more than 5 K for only optical thin liquid clouds. The changes in mass concentrations of atmospheric particles derived by the sulfur dioxide emissions are shown to be a highly possible factor to the observed cloud changes.