Fig. 6From: Ionospheric electron density modelling using B-splines and constraint optimizationMaps of the lower bound of the three key parameters \(\kappa _{1; l} = N_{m; l}^{F_2}(\varphi , \lambda )\) for the peak density (top row), \(\kappa _{2; l} = h_{m; l}^{F_2}(\varphi , \lambda )\) for the corresponding peak height (middle) and the scale height \(\kappa _{3; l} = H_{l}^{F_2}(\varphi , \lambda )\) (bottom) at three different time epochs on March 12, 2015Back to article page