On the IRI 2007 performance as a TEC predictor for the South American sector

Abstract

In order to check the performance of International Reference Ionosphere 2007 model (IRI 2007) to predict total electron content (TEC) values, we compare IRI 2007 TEC predictions against TEC measurements obtained using GPS satellites signals. The measured TEC values were obtained at nine stations in the South American sector, ranging from 18.4 to 64.7 in geographic latitude. The data correspond to June solstice and September equinox,1999, a high solar activity year. Moreover comparisons with IRI 2001 performance, studied for the same period, have been done. The results show: (i) Cases with good agreement between modeled and experimental values for minimum ionization hours. (ii) Strong disagreements in some cases for maximum ionization hours. (iii) In general, the predicted values result firstly underestimated and then overestimated as we move from low to high latitude. (iv) For middle and high latitudes, IRI 2007 calculations are better than those obtained from IRI 2001; on the contrary, at low latitudes and for daytime hours, IRI 2001 shows a better accuracy than IRI 2007.