Abstract:

The aim of this study is to evaluate the performance of NeQuick 2 model during geomagnetic storm process. For this purpose, vertical total electron content (VTEC) values obtained from NeQuick 2 model and GPS (Global Positioning System) receiver were compared for five stations selected from 5 different latitude regions during 05-09 September 2017. Comparison was made by correlation, root mean square error (RMSE) and difference taking methods. The variation of VTEC values obtained by NeQuick 2 and GPS is generally similar, although there are phase shifts and amplitude differences. The maximum correlation was observed in the equator region on the quiet days before the storm (September 5-6), but the correlation coefficient decreased as it moved away from the equator. The maximum correlation coefficient was calculated at the mid-latitude of the southern hemisphere during the initial, main and return phases of the storm. In addition, the lowest correlation was determined at high latitudes of the northern hemisphere. At all stations (except NYAL station on 05, 07, 08 / 09/2017), the maximum value of the calculated difference is smaller than the minimum value. When the GPS VTEC values are higher than the NeQuick 2 model values, the difference is generally low, on the contrary when the NeQuick 2 model values are greater than the GPS VTEC values, the difference is quite large. This shows that the NeQuick 2 model generally overestimates the TEC values

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