Zô‐Sè Observatory September to December, 1946

(Latitude 31° 06′ N., longitude 121° 11′ or 8h 04m.45 W. of Gr.)September 16–24—The equinoctial magnetic activity began at 13h 47m GMT, September 16, with an abrupt rise of 15 gammas in H which was followed by a moderate disturbance with an amplitude of 120 gammas lasting some eighteen hours. At 23h 51m, September 17, sudden commencement of a major storm occurred. H swiftly decreased by 210 gammas in two hours and moderate oscillations followed around that low value during four hours, then was a new decrease of 100 gammas. Disturbed conditions prevailed with irregular oscillations and increasing values in the morning of September 18. At 12h 10m there was a new fall of the curve by 135 gammas; milder conditions continued until 14h 56m on the 18th, when a rapid increase of 140 gammas in forty minutes and two large oscillations exceeding 100 gammas brought the curve near normal values. At 10h 10m, September 19, an increase in the activity was noted and two large oscillations of 80 gammas in range. Smooth conditions prevailed thereafter. The evening of September 20 and the morning of the 21st were calm. At 17h 13m, September 21, a new, very sharp beginning of 49 gammas preceded the major storm of the equinox. Activity at first was reduced till 04h 23m September 22, when a new rise of 20 gammas was followed by a drop of 170 gammas and the curve was slowly recovering when a violent sudden start of 45 gammas took place at 10h 11m with rapid and spasmodic fluctuations during more then eight hours. The storm was then at its maximum. Disturbance abated in the evening of the 23rd and calm was absolute near 17h of the 24th.