On the Electromagnetic Disturbance accompanying Rainor Snow-Drift

Abstract

It is occasionally experienced that the magnetic field and earth-current are disturbed by rain or snow storm. Drifting of electric charge on rain drop or snow flake by the strong wind is equivalent to an electric current, so that disturbances produced may be considered to do with the inhomogeneity of the density of the drift current which is probably due to random distribution of particle, rain or snow in the storm, and also to turbulent motion of surface wind.
The present paper deals with the relation between the variation of vertical component of the magnetic field and component of the earthcurrent parallel to the drifting direction. According to the result, the ration of the amplitude of deflections, magnetic vertical force to earth-current, is given to be √σT (σ means earth's electric conductivity, and T the period of variation), and the phase of the vertical force retarded by 1/4π to that of earth-current. The practical magnitude of variation seems to be in a fairly good agreement with the above conclusion. Moreover, it offers another method of determining the electric charge on rain drop or snow flake in the excess of one sign, when the meteorology furnishes it with the knowledge of the boundary of drifting region and wind structure.