The earth has not only a magnetic but also an electric field \(E\). Between the lower layer of the Earth's atmosphere and the ground, an electric field of approximately \( E = 130 \, \frac{\text V}{\text m} \) is measured on average, with the E field pointing toward the Earth. Consequently, the Earth's surface (assuming that the Earth is a charged sphere) carries a negative charge \(Q\), which is of the order of \(10^5 \, \text{C}\).
Since the measured E-field remains constant on time average, the charge difference between the lower atmosphere and the ground must be maintained. This happens, for example, by vertical wind currents that carry positive particles upward and by the global lightning that equalizes large charge differences between the atmosphere and the ground (during thunderstorms).
