Fig. 13From: Relationship between topography, tropospheric wind, and frequency of mountain waves in the upper mesosphere over the Kanto area of Japana Distribution of occurrence frequency of wavy cloud events enumerated based on the angle between the direction of the phase line of the wavy clouds and the background wind direction. b Relationship between the background wind speed at the altitude of 1000 m from the ground and the wavelength of wavy clouds detected over the Tohoku regionBack to article page