Fog climatology in Latvia

Fog has been recognised as a hazardous weather phenomenon that can cause accidents and affect urban air quality negatively. Therefore, assessing the characteristics of fog formation, as well as the changes in fog frequency and intensity as a result of climate change is of high importance. This study covers a 52-year period and contains an analysis of the frequency of fog occurring, long-term changes in fog frequency and atmospheric conditions that favour the occurrence of fog events in Latvia. During the analysis, two inter-annual maxima of fog frequency were identified in the spring and autumn; the seasonal differences in the formation of fog were also confirmed using satellite observations of low-level cloudiness. However, the long-term changes of fog frequency showed a decrease tendency of fog to form, which may be associated with improvements in air quality since industrialization and the observed increase of air temperature.