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ICAO service
In 2017, the International Civil Aviation Organization (ICAO) launched a call for real-time worldwide space weather service for aviation. Among three other centres, PECASUS (Pan-European Consortium for Aviation Space Weather User Services) was selected in 2018 as a global centre for broadcasting aviation alert advisories.
This international consortium, composed of Finland, Belgium, the United Kingdom, Germany, Austria, the Netherlands, Cyprus, Italy and Poland warns the aviation community about solar and geomagnetic storms that may disrupt communication and positioning systems or expose aircraft crew and passengers to high radiation levels.
On 7 November 2019, PECASUS officially began operating a 24/7 space weather monitoring service on a two-week rotational basis with the other centres.
In case of solar events that could impact airline operations, advisory messages are issued to inform the user about the type of impact (HF communication, GNSS disruptions, or enhanced radiation exposure), the expected onset or ongoing status of the event, its duration, the affected spatial region, and the estimated severity - classified as moderate (MOD) or severe (SEV).
With the Sun now entering its period of maximum activity, the challenge remains to provide space weather advisories in a timely and accurate manner.
Radiation events
As part of the STCE (Solar-Terrestrial Centre of Excellence), which serves as the data hub and is responsible for compiling the advisories within the PECASUS consortium, the BIRA-IASB Space weather group mainly provides scientific support to the operator in case of expected or ongoing radiation storms.
High energetic particles (>10 - 1000 MeV, mainly protons) released by the Sun - known as Solar Energetic Particle (SEP) events - can be ejected during solar flares or produced by shock waves induced by Coronal Mass Ejections (CMEs).
These particles can reach the top of the atmosphere, generating secondary particles that elevate the radiation levels at flight altitudes and on the ground, where they are detected as Ground Level Enhancements (GLEs) by neutron monitor stations.
Strong radiation storms that significantly increase the radiation exposure at flight level are rare and typically short-lived (~minutes to hours). However, lowering altitude and/or avoiding polar routes can significantly reduce the radiation exposure.
Reference
Space Weather Services for Civil Aviation—Challenges and Solutions, K. Kauristie et al., Remote Sens. 2021, 13(18), 3685; https://doi.org/10.3390/rs13183685.
