Scientists Develop New Radio System, Crucial During Natural Disasters

A new model for radio wave propagation through the ionosphere, developed by scientists of Indian Institute of Geomagnetism (IIG), can help estimate the impact of space weather and facilitate the planning and operation of high-frequency (HF) radio communications, a vital means of communication during emergency situation like natural disasters and mid-ocean surveillance.

The ionosphere is a region of Earth's upper atmosphere ranging from about 100-1,000 km and acts as a gateway for radio communication between the ground and space.

Radio waves of certain frequencies (HF band) are reflected back to the ground by the ionosphere, enabling long-distance HF communications beyond the horizon. This is known as 'Skywave' communications.

"Despite the increasing use of satellite communications, traditional long-distance high-frequency (HF) radio communication, remains a vital means of communication during the situations like natural disasters, mid-ocean surveillance and over-the-horizon target detection," says a Department of Science and Technology (DST) release.

Severe ionospheric disturbances that arise due to space weather events like solar flares, coronal mass ejections (CMEs), and geomagnetic storms significantly affect Skywave communications. This variability of ionosphere due to disturbances in space weather can significantly limit the usage of Skywave communications.

The scientists at IIG, an autonomous institute of DST, recently developed the HF radio wave propagation model through the ionosphere, which helps study the impacts of space weather effects on the ionosphere and Skywave communication systems.

In their recent study published in the journal 'Space Weather', the IIG scientists say they found a deep depletion of the ionosphere over the low latitudes of the Indian sub-continent region due to a severe geomagnetic storm on 17th March 2015.

The HF radio wave propagation model developed by the scientists indicates that this ionospheric depletion can severely limit the usable HF spectrum by more than half for Skywave communication during this disturbed period. Also, the skip-zones where the Skywave signals are not receivable are expanded for very large areas resulting in the loss of communications.

The HF radio propagation model developed by IIG scientists has important applications in planning the right strategies for operating Skywave communication systems during active space weather periods. The development of such strategies is essential for ensuring reliable Skywave communication systems in the face of natural disasters and other emergencies, the release said.