NeQuick 2 total electron content predictions for middle latitudes of North American region during a deep solar minimum

Abstract

The performance of NeQuick 2 model in computing the vertical total electron content (VTEC) over a wide region placed at middle latitudes of North America during the deep solar minimum that occurred in 2008 has been checked. The long term relationship between EUV irradiance and F10.7 solar flux has changed markedly during the cycle 23/24 minimum with EUV levels decreasing more than expected from F10.7 proxy. A decrease of ionization in the ionosphere could have occurred. Thus, it could be expected that the models overestimate the value of ionospheric parameters for that deep solar minimum. For this study a high density VTEC data grid that covers the Continental United States (CONUS) has been compared with monthly median maps constructed with NeQuick 2. The results show that NeQuick 2 generally gives good predictions for the region which lies between 35°N to 50°N suggesting that nothing exceptional was happening during the 2008 minimum in terms of VTEC NeQuick 2's predictive capabilities. Taking into account that the modeled value is obtained by integration in height of the electron density profile, NeQuick2 would be assuming an inadequate profile for the few highest deviations observed, between 30°N and 35°N. Overall, the model does not give significant overestimation of VTEC as could be expected.