Filling the gaps: New variometers in the UK for space weather monitoring

Three long term INTERMAGNET-standard observatories (Hartland [HAD], Eskdalemuir [ESK] and Lerwick [LER]) have operated in Britain for decades covering latitudes from 50° to61°N degrees. However, due to their location, there is limited longitudinal coverage (-1° to -4 °E) which does not provide sufficient coverage across the available 10° longitude extent of the British Isles. In 2022, three new variometer sites were installed in western Northern Ireland (Florence Court, FLO), central England (Market Harborough, LEI) and south-eastern England (Herstmonceux, HTX) to complement the existing observatory network. These provide high quality magnetic variation data, though not absolute level, for space weather monitoring. We describe the instrumentation, site environment, and data collection protocols. With the new monitoring sites we can apply the data in space weather research, for example to improve the measurement of the auroral oval extent and intensity during the May 2024 extreme magnetic storm.