The hourly mean data are from the three UK observatories Eskdalemuir, Lerwick and Hartland. Eskdalemuir data are available from 1911, Lerwick from 1926, Hartland from 1957 and all three are available up to yesterday's date. Values up to the end of 2003 have had final baseline corrections applied and are the definitive absolute hourly mean values. Data from 2004 onwards are all provisional and have not had final baseline corrections applied.
Values of declination (D), horizontal intensity (H) and vertical intensity (Z) are available. The units of declination are degrees. Declination is negative when west of true north. The units of horizontal intensity and vertical intensity are nT. Vertical intensity is positive in the downwards direction.Values from Abinger (1926-1956) are available on request.
Please note :