Characterization of GPS total electron content (GPS-TEC) in Antarctica from 2004 to 2011

Emília Correia Emília Correia,Amanda Junqueira Paz Amanda Junqueira Paz,Mauricio A Gende Mauricio A Gende

doi:10.4401/ag-6223

Abstract

<p>The vertical total electron content (VTEC) obtained from 2004 to 2011 at Comandante Ferraz Brazilian Antarctic Station (62.1°S, 58.4°W) is analyzed to study the mean diurnal, seasonal and annual variations. The maximum daytime VTEC had an annual variation that decreased from 2004 to 2008, and then starting to increase in 2009, which followed the variation of the solar activity. The daily VTEC shows good linear correlation with solar radiation intensity, which is also dependent on the solar zenithal angle. The mean diurnal VTEC shows a semiannual variation, with larger peaks in equinoxes for all years; no winter anomaly was observed, and in summer, there was no clear diurnal variation. The semiannual variation of the VTEC is also modulated by solar activity, with larger VTEC peaks when the solar activity was higher.</p>

Highlights

The total electron content (TEC) has been used to study the ionosphere behavior for different sectors, with particular interest in an understanding of its mean diurnal, seasonal and annual variations, as well as its dependence on solar activity level
From a study of the global distribution of the amplitude of various anomalies, Zhao et al [2007] showed that these are modulated by the solar activity, and that the daytime TEC seasonal anomaly is most evident at middle to high latitudes in the northern hemisphere, while the semiannual anomaly is seen at all latitudes, with it being more pronounced in the equatorial anomaly crest region (±20° magnetic latitudes)
Long-term variation – solar radiation control To study the solar influence in the long-term variation of the vertical total electron content (VTEC), we considered the daily median value obtained between 15:00 UT and 17:00 UT (~12:00 LT) as representative of the maximum daily VTEC, from 2004 to 2011

Summary

Introduction

The total electron content (TEC) has been used to study the ionosphere behavior for different sectors, with particular interest in an understanding of its mean diurnal, seasonal and annual variations, as well as its dependence on solar activity level. Most vertical (V)TEC variation studies have been carried out at equatorial and low latitudes [e.g., Huang and Cheng 1995, and references therein, Mansilla et al 2005, Galav et al 2010, Natali and Meza 2011, Liu et al 2012, Kumar et al 2012, Olwedo et al 2012]. From a study of the global distribution of the amplitude of various anomalies, Zhao et al [2007] showed that these are modulated by the solar activity, and that the daytime TEC seasonal anomaly is most evident at middle to high latitudes in the northern hemisphere, while the semiannual anomaly is seen at all latitudes, with it being more pronounced in the equatorial anomaly crest region (±20° magnetic latitudes). The winter anomaly has been more clearly observed during periods when the Sun has been highly active [Walker 1971, Huang and Cheng 1995, Mansilla et al 2005]

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Conclusion