Quantifying Total Electron Content Forecasts during Ionospheric Storms

We present approaches to forecasting total electron content (TEC) using the Global Ionosphere-Thermosphere Model (GITM), in order to explore the feasibility of ionospheric forecasts with the current generation of physics-based models. For a number of representative ionospheric storms, we present the results from GITM simulations in a forecast mode. The simulations are driven by solar wind conditions at 1 AU from either in-situ observations or predictions by one of the physics-based heliospheric models: ENLIL, CORHEL, and SWMF. To evaluate the forecasts, we compare the simulation results with TEC observations obtained from Global Positioning System satellite signals. TEC metrics are being developed that have a dual purpose: as a quantitative tool for evaluating TEC forecasts, and to characterize patterns in the responses of the storms. We introduce methods to deduce the primary physical factors responsible for the forecasted TEC responses. Statistical results are obtained and analyzed for different types of solar wind disturbances that lead to storms.