Observations and analysis of the mid‐latitude atmospheric electric field during geomagnetic activity

In this study, the diurnal and seasonal variation curves of atmospheric electric field (Ez ${E}_{z}$) are obtained, based on the extensive observations at Mohe station (Geographical coordinates: 22.357 degrees E, 53.482 degrees N and geomagnetic coordinates: 195.5 degrees E, 48.8 degrees N) of the Chinese Meridian Project. The results show that the diurnal variation of Ez ${E}_{z}$ conforms to the "Carnegie" pattern, and the value of Ez ${E}_{z}$ in winter is higher than the summer. The coupling effect of the solar wind-magnetosphere with the atmospheric electric field is established. In total, 15 cases of magnetic storms are selected while Mohe is under fair weather condition throughout the storm period. The analyzed results reveal that Ez ${E}_{z}$ exhibits the same characteristics during the 15 storms, that is, Ez ${E}_{z}$ decreases sharply and changes simultaneously with the interplanetary magnetic field (IMF) component and solar wind proton number density. When the IMF-Bz ${B}_{z}$ shifts to south, Ez ${E}_{z}$ presents a large decrease with magnitudes of about 100 V/m-600 V/m.