Featured Science
Every satellite signal travelling between Earth and space must pass through a dynamic layer of the atmosphere known as the ionosphere. Although invisible, this electrically charged region plays a critical role in communication, navigation and space-based services that millions of people rely on every day. Variations in the ionosphere can affect radio communication, introduce errors in satellite navigation systems such as GPS and NavIC, and influence the operation of low Earth orbit (LEO) satellites. Understanding these changes is therefore essential for reliable space-based services.
One of the least understood regions is the topside ionosphere, extending hundreds of kilometres above the Earth's surface. Estimating the distribution of electrons in this region has remained a scientific challenge, particularly over the Indian subcontinent where ionospheric behaviour is strongly influenced by the geomagnetic equator. Most existing models rely on simplified assumptions because of the limited availability of region-specific observations, often reducing the accuracy of ionospheric predictions.
Researchers at the Indian Institute of Geomagnetism (IIG), an autonomous institute under the Department of Science and Technology (DST), have developed a new approach to address this challenge. For the first time over the Indian region, the team has reconstructed the topside ionosphere by integrating ground-based ionosonde observations with space-based COSMIC radio occultation measurements. The method combines information from both observation systems to generate a more realistic representation of the electron density profile up to an altitude of about 1,000 kilometres, where a large number of low Earth orbit satellites operate.
Unlike conventional approaches that assume a constant topside scale height, the new technique incorporates its variation with altitude, enabling more accurate representation of the ionosphere under different space weather conditions. The study also provides improved estimates of the topside scale height gradient, an important parameter for regional ionospheric modelling.
Why the study matters
The improved modelling approach has several practical applications:
- Better prediction of ionospheric conditions over the Indian region
- Improved reliability of satellite communication systems
- Enhanced positioning accuracy for GPS and NavIC
- More accurate monitoring of space weather effects
- Better support for low Earth orbit satellite operations
The approach is particularly relevant for the geomagnetic equatorial region, where ionospheric behaviour is highly dynamic and difficult to model. By combining complementary observations from ground- and space-based platforms, the study demonstrates how integrated observation systems can improve the understanding of near-Earth space.
The research, carried out by K. Siba Kiran Guru, S. Sripathi and R. K. Barad, has been published in the AGU Radio Science journal. Beyond the Indian region, the methodology has the potential to be adapted for ionospheric studies in other parts of the world, contributing to improved space weather forecasting and more reliable satellite-based communication and navigation services.
The research, carried out by K. Siba Kiran Guru, S. Sripathi and R. K. Barad, has been published in the AGU Radio Science journal. Beyond the Indian region, the methodology has the potential to be adapted for ionospheric studies in other parts of the world, contributing to improved space weather forecasting and more reliable satellite-based communication and navigation services.
Source: https://www.pib.gov.in/PressReleaseDetail.aspx?PRID=2282424®=48&lang=1