Value chain · CLM-0155
In plain terms
A calculation from existing UK magnetic-field data shows the UK sits just inside the zone where NOAA says a strong (G3-level or worse) geomagnetic storm's aurora becomes visible, and right on the edge of where a moderate (G2) storm's aurora would be seen.
The claim as recorded
Using the standard centred-dipole relation applied to an existing IGRF-14 calculation for a UK site (52.5N, 1.5W, dipole inclination 70.08 degrees), the UK's geomagnetic latitude is approximately 54.1 degrees North, placing it about 4 degrees poleward of NOAA's G3 (Kp=7) aurora-visibility boundary (50N) and just under 1 degree equatorward of the G2 (Kp=6) boundary (55N), i.e. just outside the G2 zone and borderline.
Scope and limits
NOAA's aurora-visibility boundary describes lower-energy (order 1-10 keV) optical-aurora-producing precipitation, not the higher-energy (>15 keV) precipitation that causes D-region radio absorption; using it as a proxy for the absorption-zone boundary is a defensible approximation, not a direct measurement. No riometer or absorption dataset at 50-55 degrees magnetic latitude (matching the UK) was found to confirm this directly.
What it assumes
A simple centred-dipole approximation is adequate; the riometer-literature papers in the register use the more precise AACGM coordinate system, which can differ from centred-dipole latitude by a few degrees at these latitudes.
Where it comes from
This is the project's own working, shown in full:
Own calculation: lambda_m = arctan(tan(70.08 deg)/2) = 54.1 deg N, using tan(I) = 2 tan(lambda_m); compared against NOAA/SWPC "NOAA Space Weather Scales," G-scale aurora-visibility latitudes: G2=55N, G3=50N, G4=45N, G5=40N.
Basis: degrees magnetic latitude (centred-dipole approximation)
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-0155
CLM-0155, Energy Aperture, as of 2026.