A sensitivity analysis of empirical parameters used in physics-based models was completed in this study to determine their effect on electron densities and total electron content (TEC) in the ionosphere. The model used was the Ionosphere- Plasmasphere Model (IPM) developed by Utah State University. The empirical pa- rameters studied include the O+/O collision frequency, zonal wind, secondary electron production, nighttime E⃗ × B⃗ drifts, and tidal structure. The sensitivity analysis was completed by comparing a default run of the IPM to a run with the parameter ad- justed for three geophysical cases. Many of the comparisons resulted in nonlinear changes to the model output. Doubling the O+/O collision frequency increased NmF2 up to 250% in the equatorial anomalies. Setting the zonal winds to zero resulted in a 400% increase in TEC units (TECU) over the Southeast Pacific and a 50% decrease near Madagascar. It was found that changes in electron density and TEC are directly proportional to how daytime production is scaled to account for secondary electron production. Decreasing the nighttime downward E⃗ ×B⃗ drift resulted in a 160%–630% increase in low latitude TEC. Finally, modulating the E⃗ × B⃗ drift to simulate tidal forcing reproduced the four-wave pattern of enhanced low latitude TEC.
- ionosphere-plasmasphere model,
- physics-based models,
- space weather
Available at: http://works.bepress.com/janelle_jenniges/2/