On the Diurnal Variation of the Earth's Magnetic Field. (Second Report)

[摘要] In the first paper, it was showed that the conductivity in the ionosphere is an asymmetric tensor, and the magnetic field produced by the atmospheric oscillations was calculated, ignoring the accumulation of charge on account of no disapperance of the divergence of the current. The idea that this accumulation must be canceled by the generation of the statical field as the atmospheric electricity teaches us, brings us to the very interesting result that the electric and magnetic fields are dependent of the conductivity, instead of .We calculated the magnetic field produced by the atmospheric oscillations strictly, starting from the fundamental equations and knew that when the oscillations is similar to that observed on the earth surface and the number of ions and electrons not different exceedingly, the current in the layer, 50km in thickness, and 120km in height, gives the observed amplitudes fairly, though phase difference as of old, and in the layer having large conductivity, the component with the same period as that of the oscillation, approaches to some constant, while the others, to the negligible small in spite of the variation of the conductivity with many periods, which shows the oscillation in such height very small.Considering the eddy viscosity which is too large in the air, especially in lower atmosphere, to disregard compared with, was investigated the oscillation due to the temperature changes consisting of the two parts… the one is that limited in the lower troposphere (within about 1km) in which the eddy thermal conduction prevails, and the other that slowly diminishing with height comparatively.The result gives a good explanation to the pressure variation in the upper free air calculated by prof. Fujiwhara and Mr. Takeda using the temperature variation over Lindenberg, and shows the oscillation in the stratosphere will be about 2/1π earlier in phase than that on the ground if the coefficient of eddy viscosity is 105-107 which seems to be reliable from the theory of the land and see breeze.Besides in the ionosphere, the presence of the temperature variation will be considered by absorption of the solar radiation even if it is not so large as some investigato_??_s believe.In any case, the diurnal variation of the earth magnetic field will be thoroughly explained, both in amplitude and in phase, by the atmospheric oscillation forced either by the one or two of the temperature changes in the lower atmosphere and in the stratosphere which must be expected to the further observations in future. Details will be published in The Geophysical Magazine in near future.

[学科分类] 大气科学