Abstract
Over complex, mountainous terrain the near‐surface winds can form intricate patterns as large‐scale winds and locally forced wind systems interplay. Switzerland, with its mountainous topography and dense meteorological network of 115 automated surface stations, ideally serves as a study area for such wind system interactions. Applying an automated classification scheme to the wind data of one single year (1995), 16 distinct near‐surface flow patterns were found. These patterns also show characteristic distributions in magnitude and areal extent of temperature, global radiation and precipitation. An 18‐year climatology of flow patterns was created with an identification method for fewer stations. This allowed the determination of annual and diurnal variations in the frequencies of occurrence of the different flow patterns, revealing pronounced daytime and night‐time classes characterized by thermally forced winds. Transition probabilities between the flow patterns were computed as well. The relationship between the near‐surface wind patterns and the synoptic flow situation was investigated with a comparison with synoptic weather types defined for the Alpine region. The results show clear but not unequivocal interdependencies between the synoptic weather type and the near‐surface flow pattern. Copyright © 2001 Royal Meteorological Society