Reply to comment by B. E. Prokhorov and O. V. Zolotov on “An improved coupling model for the lithosphere-atmosphere-ionosphere system”

The currents flowing between the Earth and ionosphere are numerically calculated. We solve the current continuity equation by two methods: the first method is to solve empty set in del . J = del. (sigma del empty set) = 0, where sigma is atmospheric conductivity and empty set is the electric potential, and the second method is to solve the current potential psi in del . J = -del(2.) J = -del(2) psi = 0 by assuming J = -del psi a curl- free current density. Two solutions of del . J = 0 for current flow in the atmosphere between Earth surface and ionosphere are compared in this reply. The differences of two results are < 4%, which may be partly caused by the numerical errors in the presence of large variations in the sigma profile. The current potential can provide a good approximation for upward currents that flow into the ionosphere. In addition, we compare two models for the current flow from lithosphere to atmosphere: ( a) two charge layers embedded in the lithosphere and ( b) a dynamo in the lithosphere. The presence of a dynamo in the lithosphere for Model ( b) can lead to the presence of current and electric field in the atmosphere and hence in the ionosphere. In Model ( a), the electrostatic charge layers in the lithosphere cannot lead to the presence of electric field in the atmosphere.