Measurements of the amount of ozone in the Earth’s atmosphere and its relation to other geophysical conditions.—Part III

Abstract

The work described below is a continuation of that given in the former paper—Parts I and II. The main object was to study the distribution of ozone in cyclones and anticyclones. This has now been completed as far as seems possible by private research, and most of the instruments have been sent to new stations in distant regions of the globe in order to obtain a general idea of the distribution of ozone over the world. It must be remembered, however, that the study of the ozone distribution in cyclones and anticyclones has really been exceedingly meagre. If, when synoptic meteorology began to be studied, the same number of barometric observations had been taken at six stations, they would hardly have led to an accurate knowledge of cyclones and anticyclones ! There may be much of great interest that has been entirely missed in this research, but further work must be left to larger organisations, as it was found that the present investigation using only seven stations taxed individual efforts to the uttermost: over 5000 spectra have been measured at Oxford in the course of the routine work. The observations have been made at the same stations as those described in Part II and the instruments are the same as those used before. In the previous papers the amount of ozone was calculated on the assumption that the ozone was near the ground. Evidence has now been obtained that it is situated at an average height of about 40 to 50 km. In this paper allowance has been made for this. The difference is only appreciable when observations are made with the sun at less than 30° above the horizon and the error in the previously published results is always small. Unfortunately a slight defect developed in the optical wedge of the instrument at Valentia, making the ozone values rather uncertain. As the making and calibration of a new wedge would have put the instrument out of use most of the summer it was decided to use it in its defective condition. The Valentia values are therefore a little uncertain, but the error is seldom more than 0⋅01 cm., so that it is only just appreciable when considering the ozone distribution.