Application of Slepian theory for improving the accuracy of SH‐based global ionosphere models in the Arctic region

Abstract

AbstractDue to significant energy resources in polar regions, they have emerged as strategic parts of the world. Consequently, various researches have been funded in order to study these areas in further details. This research intends to improve the accuracy of spherical harmonic (SH)‐based Global Ionospheric Models (GIMs) by reconstructing a new map of ionosphere in the Arctic region. For this purpose, the spatiospectral concentration is applied to optimize the base functions. It is carried out using the Slepian theory which was developed by Simons. Here the new base functions and the corresponding coefficients are derived from the SH models for the polar regions. Then, VTEC (vertical total electron content) is reconstructed using Slepian functions and the new coefficients. Reconstructed VTECs and the VTECs derived from SH models are compared to the estimates of this parameter, which are directly derived from dual‐frequency GPS measurements. Three International Global Navigation Satellite Systems Service stations located in the northern polar region have been used for this purpose. The starting and ending day of year of adopted GPS data are 69 and 83, respectively, (totally 15 successive days) of the year 2013. According to the obtained results, on average, application of Slepian theory can improve accuracy of the GIM by 1 to 2 total electron content unit (TECU) (1 TECU = 1016 el m−2) in the Arctic region.