This set of key parameters from the SESAME (Satellite Experiments Simultaneous with Antarctic Measurements) ground-based experiment contains equivalent overhead absorption data that are measured at 45 degrees to vertical in N,S,E,W directions in an L-shell-aligned coordinate system (ie rotated 17 degrees anti-clockwise from geographic). Preliminary Quiet-Day Curve is used. The data is accurate to 0.05dB, but possible baseline uncertainties of +/-0.5dB; with 1 minute data representing 'spot' values of the 1Hz sampling. Please see references: The multiple riometer system at Halley, Antarctica, in
British Antarctic Survey Bulletin, no 72, p13-23, 1986; and Dudeney, J. R. et. al., Satellite Experiments Simultaneous with Antarctic Measurements (SESAME), Space Science Reviews, Volume 71, Issue 1-4, pp. 705-742, 1995.