MOSAIC Digital Environment Feasibility Study

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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 (Cabinet Office, 2018). One significant risk is created by 'hard' solar particle events containing a significant flux of highly energetic particles which can lead to corruption and damage in modern microelectronic technology at ground level. In general such solar events are detectable at the earth's surface by ground level neutron monitors and are termed ground level enhancements (GLEs): they typically have durations of some hours and the most intense ever measured was in February 1956 in the UK. Prior to the 1940s however we have only indirect measurements of GLEs from ice cores and tree rings (Miyake et al, 2012; Mekhaldi et al, 2015). Results on 10Be, 36Cl and 14C show events some 30 times larger than February 1956 in AD774 and 15 times larger in AD994. In today's technological society GLEs present a hazard to complex systems, such as autonomous vehicles, railways, nuclear power stations and especially aircraft (including unmanned aerial platforms) which are by far the most exposed. At present the UK has no ground level neutron measurement capability as this was abandoned in the 1980s. The main objective of the Moisture Sensors for Atmospheric Ionising Collaboration (MOSAIC) project is to study dual-purposing the UK COSMOS soil moisture sensor network to provide an unprecedented, high-density, sustainable and cost-effective UK space weather measurement capability to provide real-time alerts for critical infrastructure as well as enabling new environmental science. COSMOS is a relatively new and expanding network of sensors and there are now nearly 50 detectors across the UK operated by the NERC Centre for Ecology and Hydrology (CEH). Neutrons generated by cosmic-rays high in the atmosphere can reach ground level, some of which will be reflected dependent on the soil moisture content: COSMOS stations measure the reflected neutrons to determine average soil moisture over the local area. Besides studying the prospect of operational warnings for infrastructure (including aviation) there is an opportunity to create a long term record of ground level neutron radiation in the UK which can be the basis of better environmental models and improved risk assessments for government.The study examine COSMOS sensitivity to GLEs along with the digital network feasibility issues which would arise when dual-purposing the network. An initial priority is to examine the practicality of significantly higher temporal resolution which will be needed for MOSAIC given that GLE rise times can be of the order of minutes. We will examine the feasibility of achieving very rapid communication of data from the sensors to the centre(s) where decisions are taken on the need to issue alerts and how long this might take. It is likely that the geographical diversity and distributed nature of the COSMOS digital network could offer significant benefits for robustness via the inherent redundancy compared to conventional 'single point' monitors. To assist this work the Met Office will act as the primary 'user' of the system and will advise on their data distribution and processing requirements and we will investigate how artificial intelligence can better distinguish the wanted signal and enhance decision accuracy. We will also investigate how MOSAIC can be integrated with the Surrey Smartphone Atmospheric Ionising RAdiation network or SAIRA which has already demonstrated a citizen science approach to obtain complementary radiation data from aircraft.