Modeling the Seasonal Dynamics of the Diurnal Variation of the Global Electric Circuit

Abstract

On the basis of a parametrization of the ionospheric potential (IP), the seasonal dynamics of the diurnal IP variation for 2016–2017 is simulated for the first time using the Weather Research and Forecasting (WRF)-Advanced Research WRF (WRF-ARW) model. The diurnal IP variation averaged over the annual simulation period shows good agreement with the classical Carnegie curve, suggesting that the proposed parametrization correctly reproduces the basic characteristics of stationary global electric circuit generators. The annual variation shows no precise repeatability from year to year, but there is a lower IP in the Northern Hemisphere winter and a higher value in the summer. The model-derived diurnal variation demonstrates stable seasonal trends, with only one distinct IP maximum of 120% of the average at 16:00 to 18:00 UTC in the Northern Hemisphere winter and two much lower maxima (~107% of the average) in the summer: a morning maximum at 08:00 to 09:00 UTC and an evening maximum at 18:00 to 20:00 UTC. The model annual dynamics of the diurnal variation agrees with the experimental data of surface field measurements in Antarctica in 2006–2011. The proposed parameterization and the modeling technique made it possible to correctly simulate the times of IP variation maxima, their seasonal variability, and а decrease in the variation amplitude during the Northern Hemisphere summer.