| Abstract | This work analyzes different current source and conductivity parameterizations and their influence on the diurnal variation of the global electric circuit (GEC). The diurnal variations of the current source parameterizations obtained using electric field and conductivity measurements from plane overflights combined with global TRMM satellite data give generally good agreement with measured diurnal variation of the electric field at Vostok, Antarctica, where reference experimental measurements are performed. An approach employing ice scattering signals from 85-GHz passive microwave observations to infer currents within the GEC is compared and shows the best agreement in amplitude and phase with experimental measurements. To study the conductivity influence, GEC models solving the continuity equation in 3-D are used to calculate atmospheric resistance using yearly averaged conductivity obtained from the global circulation model CESM1(WACCM). Then, using current source parameterization combining mean currents and global counts of electrified clouds, if the exponential conductivity is substituted by the conductivity from CESM1(WACCM), the diurnal variation of the ionospheric potential of the GEC decreases from 10% to 6%. The main
reason for the change is the presence of clouds while effects of 222 20 Rn ionization, aerosols and topography are small. The simulated diurnal variation of the electric field at Vostok is different by less than 2% from the diurnal variation of the global current in the GEC if conductivity from CESM1(WACCM) is used. |
