Abstract
In the eastern part of Asiatic Continent, mainly in the eastern part of Tai-hang Mountains and southeastern part of Khingan Mountains, dust-storms occur frequently and sometimes reach the central part of Japan. They corresponds to the dust-storms in the eastern part of Rocky Mountains in America. Such flying sand particles are called “Kosya”, which means yellow dust, in our country.
The dust-storms occur most frequently in spring as in America. In spring many cyclones with fresh cold fronts, along which TA masses are forced to rise by PA masses, are generated in the regions of South Manchoukuo and North China. Very dry sand particles are lifted up to about 4000m by ascending currents caused by cold ronts and carried away with upper air currents of the moving anticyclones whereby the sand particle, descend continuously. The actual falling velocities of sand particles (5μ-25μ) agree with the velocities calculated by the formula of Stokes-Cunningham. The diminution of solar radiation by “Kosya” is on the average30% of the normal day at Hukuoka, about 1400 kilometers of distance from the origin.
