Calculated and measured values of liquid water content in clean and polluted environments

The relationship between liquid water content (L WC) and visibility (VIS) in a fog was examined by afield measurement of LWC values at a clean location of the meteorological observatory Sodankyla (Finland) and in a polluted region at the meteorological observatory Mileovka (Czech Republic). Furthermore, the use of a simple regression fog model to determine LWC from VIS is examined by comparing well-known relationships with the measurement results. The results show that the verbal characterization of environment (clean, mild polluted, polluted) is insufficient to calculate the L WC values from visibility. It is necessary to establish an additional criterion based on quantitative fog characteristics or to determine the site-related equation from the previous LWC and VIS measurement.