Abstract
The distribution of wind velocity near the earth's surface was calculated, assuming that the atmosphere is built up of two layers which have different eddy viscosities. And the following relation between surface and gradient winds was derived: where v1 and v2 are kinematic eddy viscosities of two layers, h thickness of lower layer, λ and η constants dependent on latitude. Next, the angle between wind directions and the ratio _??_ were measured from the synoptic chart and their mean values were calculated. It was found that the angle and ratio vary with the seasons and it was explained by the seasonal variation of the stability of lower layer.
