Electric Field Measurements in the Antarctic Reveal Patterns Related to the El Nino-Southern Oscillation

Electric field measurements at Vostok station in Antarctica reveal that the El Nino-Southern Oscillation (ENSO) has a statistically significant effect on the global electric circuit, as earlier predicted by simulations. Analysis of 10 October-February periods during 2006-2016 indicates that the shape of the diurnal variation of the surface electric field is significantly different for El Nino and La Nina years, with an especially pronounced deviation during the super El Nino of 2015/16. During strong El Ninos the potential gradient relative to the diurnal mean is generally higher than usual around 8:00-14:00 UTC and lower than usual around 16:00-0:00 UTC; La Ninas are characterized by the opposite behavior. Simulations with the Weather Research and Forecasting model imply that the observed patterns are the result of changes in the global distribution of electrified clouds over the Pacific Ocean, Maritime Continent, and South America during ENSO events.