Improvement of topside ionosphere and plasmasphere estimation in ionospheric simulation system

This work is based on the results for a complete solar cycle of 11 years (2011–2021) from the ionospheric simulation system used in the Brazilian Space Weather program. The electron density profiles generated were integrated in height and compared to the International GNSS Service (IGS) vertical total electron content (vTEC) data. Experiments have shown an inadequate electron concentration decay with height which led to an overestimation in TEC values. We propose an improvement for the topside ionosphere and plasmasphere modeling in the system, considering recent advances in empirical modeling through observational data. The idea is to combine bottomside ionosphere estimates from the physical-based core model with NeQuick analytical formulation for ionospheric profile above hmF2. Our approach also calculates the ionospheric parameters for topside modeling using bottomside estimates. The ionospheric density profile decay obtained with the proposed approach was smoother and sharper, reaching a reduction of approximately 1 to 2 orders of magnitude of electron concentration in plasmasphere. It was observed a coherent reduction of high altitudes ionosphere/plasmasphere contribution to TEC. Also, the TEC values obtained using this hybrid solution were much closer to the International GNSS Service (IGS) data for the considered dataset, with root mean squared error (RMSE) of only 2.64 TECU for the entire period.