Solar Activity and Atmospheric Ozone

Abstract

A statistical investigation of the variation of total ozone amount as measured by the deviation of ten-day running means to find out the influence of intense solar flares or of an intense solar corpuscular bombardment was carried out, each concerning with varying latitudinal belt.
The method of calculation was the key day test or the superposed epoch method to see the variation from three-days before through ten-days after the key day. The ozone data used were those of twenty-two stations of the world namely, of Japan (5), America (5), Australia (3), Italy (3), Iceland (1), India (4) and of Switzerland (1), covering the period from January 1958 to March 1959.
Key days were defined in two ways, namely the day when geomagnetic Ap index was greater than 45 and the day when the flare index, as defined by this author basing on the world wide flare data, was greater than 1500.
According to the results of calculation ozone increased on the third or forth day after the flare key day except in the zone of lowest latitude. The statistical test did not show in general a property so much remarkable as to exceed the 5% confidence limit except the increase of ozone on the third day in the zone of 20∼30° latitude.
In the case of geomagnetic key day generally none of the variation exceeded the 5% confidence limit except the case of 8 th day at the highest latitudinal belt. Also at the same zone it showed the tendency to decrease on the third day which is to be noted when compared with the increase of temperature at 100mb in the auroral zone that was reported by Ward.