THE GLOBAL ATMOSPHERIC ELECTRIC-CIRCUIT AND GAEM

Electrical currents and fields in fair weather near the surface of the earth are part of a global circuit. Thunderstorms are the main source generators. The classical model of a global circuit assumes an equipotential layer at high altitude to act as the connecting link between thunderstorms and fair weather areas. Recently, evidence is mounting that extraterrestrial sources of currents and ionization do modulate the global circuit to a measurable degree. Electric fields at the surface and at balloon altitude correlate at times with geomagnetic activity or solar flares. Problems associated with detecting such modulations are inadequate measurement techniques, local space charge noise, and the need to maintain widely spaced observation stations with good time synchronization. Newer modeling efforts have included non-isotropic current flows along magnetic field lines and thus opened the global circuit to the study of influences from extraterrestrial sources. An international project on Global Atmospheric Electricity Measurements (GAEM) has been defined. Measurements will focus on synchronized measurements of electric field and Maxwell current densities in the time domain of seconds to hours and their correlation to solar variability.