METEOROLOGY.

Press, Volume LXVII, Issue 20427, 23 December 1931, Page 10

METEOROLOGY.

—:—4 NEW LINE OF RESEARCH. OZONE CONTENT OF THE AIR. [THE PRESS Special Service.] WELLINGTON, December 22. "It will produce useful information and enable us to understand atmospheric processes better and, perhaps, some day there will be a slight' improvement in forecasting as a result of it." These were the words used on his .return to New Zealand to-day by Dr. E. Kidson, Director of Meteorological Services, when referring to the probable outcome of an extraordinary new line of research for which an instrument has just been developed by Dr. G. M. V. Dobson, lecturer in meteorology at Oxford University. Dr. Dobson has been interested for some time in the correlation of the ozone content of the air with weather . processes. He developed a few years ago a photographic instrument, . of which copies were sent to various parts of the world for the purpose of making observations of the sun with a view to determining the ozone content under different sky conditions. One of the instruments. which are not unlike long cameras, was sent to Dr. C. C. Pair at Canterbury College, who mado a series Of observations with it. The instrument of which Dr. Kidson spoke to-day is a later development in connexion with the same line of research. It is referred to as a photo-electric spectrometer, or a spectrophotometer, and it has incorporated in it a photo-electric cell made of calcium. "The solar radiation is measured in various parts by means of its action on the photo-electric cells, said Dr. Kidson explaining the new development. "By measuring the intensity of the radiation in two different portions of tho ultra-violet end of the spectrum, the observer is able to estimate ' the total amount of ozone in the atmosphere at any time. Just recently" Dr. Dobson has been able to extend his observations to the period of moonlight, and estimate tho amount of ozono at night time. Through being able to measure during both day and night, they are able to say that there is very little diurnal variation in the ozone content. It is found that tliere is a close relation between the distribution of ozono and pressure systems such as a cycloue and an anti-cyclone. Just in the rear of the centre of a cyclone ozone is abnormally plentiful, whereas in an anti-cyclone it is comparatively little. "It has also been found," Dr. Kidson went on to say, "that there is an annual variation in tho amount of ozone. It is greatest in the winter and least in the summer. It has been discovered also that tho ozoiie content is high over the Polar regions during the Polar night, while in equatorial regions there is comparatively little. It looks, therefore, as if the Polar regions were the chief source of atmospheric ozone. By means of observations at various times of the day it is possible to get a rough estimate, of the height of the atmospheric layers in which the ozone occurs. The measurement of the amount of ozone at frequent intervals will probably prove to be the means of determining atmospheric currents in the very high levels."