Resolutions passed by the Commission for Terrestrial Magnetism and Atmospheric Electricity of the International Meteorological Committee at Zürich, September 1926

Abstract

(I) Dr. Venske called attention to certain advantages for the purpose of magnetic characterization possessed by a day starting at Greenwich noon, and suggested that the attachment of a dash to the character figures 0 and 1, to signify an enhanced amount of disturbance, would introduce increased precision. In view, however, of the fact that the Section of Terrestrial Magnetism and Electricity of the International Union of Geodesy and Geophysics had arranged in Madrid in 1924 for a report, to be submitted in 1927 at Prague, on characterization, it was considered inadvisable to make any change at present.(II) In view of the desirability that the same days should be employed at all stations for the deduction of diurnal inequalities on disturbed days, and in view of the great liability to loss of trace at stations in high latitudes on occasions of outstanding disturbance, it was agreed that certain days included amongst the five most disturbed days of the month should not be included amongst the days selected for the calculation of diurnal inequalities. Days of character 2.0 should be excluded, and other highly disturbed days on which loss of trace had occurred. Directors of Observatories were to be requested to inform Prof. E. van Everdingen promptly of such loss of trace, so that he should be in possession of the necessary information at the appropriate time.