2 papers
astro-ph.SR2016
Tests of Sunspot Number Sequences: 1. Using Ionosonde Data
M. Lockwood, C. J. Scott, M. J. Owens +2
More than 70 years ago it was recognised that ionospheric F2-layer critical frequencies had a strong relationship to sunspot number. Using historic datasets from the Slough…
astro-ph.SR2015
Tests of sunspot number sequences: 3. Effects of regression procedures on the calibration of historic sunspot data
M. Lockwood, M. J Owens, L. Barnard +1
We use sunspot group observations from the Royal Greenwich Observatory (RGO) to investigate the effects of intercalibrating data from observers with different visual acuities. The…