SWIMMR Aviation Risk Modelling (SWARM)

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There is growing awareness of the hazards arising from space weather which are now listed on the UK National Risk Register. One significant risk is created by 'hard' solar particle events containing a significant flux of particles with energies greater than 300 MeV. In general such solar events are detectable at the Earth's surface by ground level neutron monitors and are termed ground level enhancements (GLEs) and typically have durations of some hours, the most intense so far measured being in February 1956 in the UK. GLEs present a hazard to modern complex systems, especially aircraft, as the particles generated in the atmosphere can cause malfunctions and damage to microelectronic technology. In addition undesirable levels of effective dose to aircrew and passengers can arise during GLEs. The International Civil Aviation Organization (ICAO) has recently identified the need to improve space weather radiation information provided to aircraft but to do so will require a widely distributed observational network, accompanied by validated radiation environment models to interpolate between observation sites and interpret the data into the effects of concern (effective dose rates and electronic upset rates). In parallel the Met Office, which is the UK government's 'owner' for space weather risks and a major provider of meteorological services for ICAO airlines, has recognised that it does not currently have the capability to provide the necessary services for space weather radiation hazards. Consequently SWARM will develop a new data-driven atmospheric radiation model (Model for Atmospheric Ionising Radiation Environments, or MAIRE+) based on an existing prototype (MAIRE) to enable the Met Office to nowcast the secondary particle fluxes, biological dose rates and electronic upset/failure rates throughout the atmosphere arising from both galactic cosmic rays and GLEs. To drive MAIRE+, real-time ground level neutron monitor data, geomagnetic disturbance indices and sunspot indices will be used. Global maps based on the ICAO global grid (15 degrees longitude, 10 degrees latitude) covering altitudes up to 60kft with 3kft altitude resolution will be provided. The dose rate maps will allow Met Office to issue alerts based on the ICAO thresholds for the affected regions. Internal models and tools will be revised to account for the most recent scientific knowledge, including updating cosmic ray and magnetic field models and improving calculations of biological dose and upset/failure rates in electronics. The new MAIRE+ model will be delivered to the Met Office and then a lengthy period of operation and validation will follow using live data sources to assess its performance. SWARM will also develop new and challenging capabilities such as increasing the model validity range to 100km altitude for GLEs (which will be important for future space tourism and high altitude aviation) and forecasting the time-profile of a GLE once it has started. For the latter, advanced models of interplanetary propagation of particles emitted from the Sun will be used and their particle energy range increased to deal with the energies required for GLEs. These new features will be incorporated into a 'research' model 'MAIRE-R' (also delivered to the Met office), however it will necessarily be less mature than the nowcast model. Finally, to address the extremely difficult problem of predicting the onset of a GLE, we will review the evidence from the historic record to determine if any solar precursor signatures for this sub-set of events can be found which could prove a valuable aid to Met Office forecasters.