A single‐station empirical model for TEC over the Antarctic Peninsula using GPS‐TEC data

Abstract

Compared with regional or global total electron content (TEC) empirical models, single‐station TEC empirical models may exhibit higher accuracy in describing TEC spatial and temporal variations for a single station. In this paper, a new single‐station empirical total electron content (TEC) model, called SSM‐month, for the O'Higgins Station in the Antarctic Peninsula is proposed by using Global Positioning System (GPS)‐TEC data from 01 January 2004 to 30 June 2015. The diurnal variation of TEC in the O'Higgins Station may have changing features in different months, sometimes even in opposite forms, because of ionospheric phenomena, such as the Mid‐latitude Summer Nighttime Anomaly (MSNA). To avoid the influence of different diurnal variations, the concept of monthly modeling is proposed in this study. The SSM‐month model, which is established by month (including 12 submodels that correspond to the 12 months), can effectively describe the diurnal variation of TEC in different months. Each submodel of the SSM‐month model exhibits good agreement with GPS‐TEC input data. Overall, the SSM‐month model fits the input data with a bias of 0.03 TECU (total electron content unit, 1 TECU = 1016 el m−2) and a standard deviation of 2.78 TECU. This model, which benefits from the modeling method, can effectively describe the MSNA phenomenon without implementing any modeling correction. TEC data derived from Center for Orbit Determination in Europe global ionosphere maps (CODE GIMs), International Reference Ionosphere 2012 (IRI2012), and NeQuick are compared with the SSM‐month model in the years of 2001 and 2015–2016. Result shows that the SSM‐month model exhibits good consistency with CODE GIMs, which is better than that of IRI2012 and NeQuick, in the O'Higgins Station on the test days.

A New Global Total Electron Content Empirical Model

“…Some empirical models also show similar situations in describing anomalies. For example, the NeQuick2 model can describe EIA phenomena [30], but it does not effectively reproduce MSNA phenomena [31]. The descriptive ability of the NeQuick2 model for EIA is also closely related to the intensity of solar activity.…”

A single-station empirical TEC model based on long-time recorded GPS data for estimating ionospheric delay

“…Besides, the GPS-TEC data are further selected under geomagnetic conditions. In some related studies, the Ap index not exceeding 30.0 is considered as quiet geomagnetic conditions (Hedin, 1984;Feng et al, 2016Feng et al, , 2017b. Following the previous studies, only the GPS-TEC data for which Ap index under 30.0 are used for modeling.…”

“…The NTCM-GL model proposed by Jakowski et al (2011b) describes the daily variation of the TEC as a combination of the diurnal, semi-diurnal, and ter-diurnal fluctuations, with diurnal TEC peak fixing at 14:00 LT. To keep the number of coefficients small as required in some applications the fixing might be justified being aware that the model accuracy is reduced. On the other hand, fixing of maximum TEC values is not set in some other similar models (Jakowski et al, 2011a;Hoque & Jakowski, 2012;Mukhtarov et al, 2013;Feng et al, 2016Feng et al, , 2017bHajra et al, 2016). Following the latter method, the diurnal variation component of the single-station model SSM-T1 proposed in this work does not set the parameters in relation to the maximum time of the TEC, but further refines the diurnal component.…”

“…In practical applications, an ionospheric empirical model is one of the vital means for ascertaining the TEC. An ionospheric empirical model based on the analysis of the ionospheric spatiotemporal variation and long-time recorded observation data can be established by a reasonable function (Jakowski et al, 2011a;Hoque & Jakowski, 2012;Mukhtarov et al, 2013;Feng et al, 2016Feng et al, , 2017aFeng et al, , 2017b.…”

“…A global empirical TEC model based on the TEC data can depict the temporal and spatial variations of the TEC in general. However, some global empirical TEC models may have low precision and fail to accurately express the variations of the ionosphere in some local regions (Feng et al, 2016(Feng et al, , 2017b. Two likely factors restrict the accuracy of empirical TEC models.…”