The Ionosphere is part of Earth's upper atmosphere, between 80 and about 600 km where Extreme UltraViolet (EUV) and x-ray solar radiation ionizes the atoms and molecules thus creating a layer of electrons. The ionosphere is important because it reflects and modifies radio waves used for communication and navigation.
Decade-long ionospheric observations at Bharati station, Antarctica, found a substantial seasonal variation with maximum total electron count (TEC) in equinoctial months followed by the summer and winter. The TEC is a key parameter that is used to understand the effects of ionosphere on satellite-based navigation and communication signals.
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| India's Bharati Research Station, Antarctica |
The ionosphere at polar regions is highly dynamic and acts as a major energy sink for space weather events, and related processes in magnetosphere-ionosphere systems as the magnetic field lines are vertical in this region. The ionospheric observations in Antarctica are few compared to Arctic region due to geographic limitations and limited number of stations.
A team of scientists from the Indian Institute of Geomagnetism (IIG), an autonomous body of the Department of Science and Technology (DST) have examined the long-term seasonal ionospheric observations at Indian Antarctica station Bharati between 2010 and 2022 and also with solar activity following Sun’s 11-year cycle.
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| Bharati Research Station |
It was observed that though there was no sunlight incidence throughout the day in winter months (polar nights) at Bharati station; a diurnal pattern was observed with peak ionospheric density near local noon. The day-night ionospheric density variations were observed regardless of 24 hours of sunlight in summer and complete darkness in winter. The scientists attributed the peak ionization to particle precipitation and transportation of convectional plasma from high latitudes. Also, the maximum ionospheric density in the summer months where 24 hours sunlight is present (polar days), was about twice more than that of polar nights at the Bharati region.
The study was published in the Journal of Polar Science. This kind of long-term studies will help understand effects of ionosphere on satellite-based navigation and communication systems and to mitigate them.
The study was published in the Journal of Polar Science. This kind of long-term studies will help understand effects of ionosphere on satellite-based navigation and communication systems and to mitigate them.
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