The average tropospheric ozone content and its variation with season and latitude as a result of the global ozone circulation

Evaluations of radiosonde soundings over North America and Europe, measurements aboard commercial airlines, and permanent ozone registrations at nineteen ground-based stations between Tromsö, Norway, and Hermanus, South Africa, yield three belts of higher ozone intrusion from the stratosphera and maximum values of the annual means at about 30°N, at between 40°–45°N and at about 60°N. A marked decrease of the annual mean values of the tropospheric ozone is detected towards the equator and the pole, respectively.In the northen hemisphere the maximum of the annual cycle of the tropospheric ozone concentration occurs in spring at high latitudes and in summer at mid-latitudes.For the tropical region from 30°S to 30°N a strong asymmetry of the northern and southern hemisphere occurs. This fact is discussed in detail. The higher troposphere of the tropics seems to be a wellmixed reservoir and mainly supplied with ozone from the tropopause gap region in the northern hemisphere. The ozone distribution in the lower troposphere of the whole tropics seems to be controlled by the up and down movements of the Hadley cell. The features of large-scale and seasonal variation of tropospheric ozone are discussed in connection with the ozone circulation in the stratosphere, the dynamic processes near the tropopause and the destruction rate at the earth's surface.     

A new automatic ozone recorder for near-surface measurements working at 19 stations on a meridional chain between Norway and South Africa

An instrument is presented which enables an automatic and permanent record of the local atmospheric ozone concentration. The well-known process of depolarization is modified. The anode and the cathode are separated so that the iodine formed by the anode is continuously removed by a slow stream of solution of potassium iodide. The calibration of the instrument, obtained with two different and independent methods, agree satisfactorily with the values calculated theoretically. Permanent records during 18 months at 19 stations between Tromsö, Norway, and Hermanus, South Africa, prove the ability of the instrument.     

Meridional distribution of tropospheric ozone from measurements aboard commercial airliners

Aboard commercial airliners twenty registrations of the ozone concentration of the upper troposphere were carried out within a period of 14 months between Europe and South Africa. Nearly each of these meridional ozone profiles shows an approximately constant ozone content between 25°S and 25°N with a pronounced seasonal variation. Most of these profiles show two marked peaks of the ozone concentration at about 30°N and between 40° and 45°N. Though the number of these registrations is not sufficient for statistical computations, the first results confirm the meridional ozone distribution, which was expected from studies with ozone-radiosonde soundings. Moreover a strong asymmetry of the northern and southern hemisphere is confirmed by these ozone measurements.     

Meridional distribution of tropospheric ozone from ground-based registrations between Norway and South Africa

By means of a meridional chain of 19 stations between Tromso, Norway, and Hermanus, South Africa, a permanent registration of ozone near the ground has been obtained since 1970. From the first year of operation surprisingly systematic annual variations come out, which agree with theoretical calculations on stratospheric-tropospheric exchange.