The earth has a vertical electric field at the surface, pointing down, that averages 107 N/C. This field is maintained by various atmospheric processes, including lightning. What is the excess charge on the surface of the earth?

Planet is all but a complete sphere and its conductor so we can presume that the net charges present on the inside of the planet is considered to be equaled to zero, so we got our self having more charges present on the surface of the planet.So, for such reasons we say that there is a net vertical charges on the planet's surface which is maintained by various atmospheric processes, including lightning.So, after concluding all of the equations and mathematical analyses we can say that the net charge on the planets surface will be be much higher then we can expect. Just because a lot of energy transmission happens on the surface of this planet.