The spatial correlation of snowfall rate has been studied in relation to the mean trajectory of the snow cloud. From the analysis of hourly data of the snow depth at 11 stations in Aomori City for the period of December 1987 through March 1988, it is found that the high correlation zone lies along the mean wind direction. This suggests that the high correlation zone indicates the mean trajectory of sonw cloud which may correspond to the mean wind direction in the upper air of 1-1.5 km above the surface. Daily data of the snow depth at 127 stations in Aomori Prefecture for the period of January 1979 through February 1985 have been analyzed in order to estimate the mean trajectory of snow cloud. It is found that the snow clouds are generally transported by the west winds of winter monsoon in a wide area of Aomori Prefecture. However, the trajectories make a detour around Mt. Hakkoda in the neighborhood of Aomori City, and the trajectories in the northern part of Tsugaru Peninsula suggest that northwest winds prevail there owing to the orographic effect. The above trajectories correspond well with the mean wind directions observed at the surface meteorological stations. In the southern part of the Tsugaru Plain, on the other hand, the estimated trajectories imply that the snow clouds are most effectively transported by northwest winds.
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