The fair-weather electric field is measured to be an average of 120 volts per meter directed downward to the ground. It decreases exponentially with height with the air density (because the dielectric strength decreases causing the atmosphere's conductivity to increase).
FAIR-WEATHER ELECTRIC FIELD
Meaning of FAIR-WEATHER ELECTRIC FIELD in English
Weather and meteorology English vocabulary. Английский словарь погоды и метеорологии . 2012