O3 Locally believed to be solved but regional unsolved

Other widely unknown ozone data from the Soviet Union measured in Moscow and in the Caucasus Mountains (Konstantinova-Schlesinger 1937a, 1937b, 1938), 

The British Antarctic survey set up stations in Antarctica. And so we d been monitoring very many things in Antarctica for a long while. And suddenly in 1985 it dawned on us that we were sitting on top of one of the biggest environmental discoveries of the decade, I suppose, or perhaps even of the century. We 

The vertical distribution of ozone is derived by the Umkehr method. Direct solar intensity is measured at two different wavelengths, one being more absorbed by ozone than the other. At sunrise and sunset, the intensities decrease at different rates. The ratio shows an inversion. This is called the Umkehreffekt and gives information about the vertical distribution of ozone in the atmosphere. An Umkehr measurement takes about three hours, and provides data up to an altitude of 48 km, with the most accurate information for altitudes above 30 km. 

Some modern versions of the Dobson spectrophotometer exist and continue to provide data, e. g. the Brewer spectrophotometer in the WMO-GAW ozone observing system comprises more than 100 stations worldwide that measure total column O3 and O3 profiles in the troposphere and stratosphere. Fig. 2.82 shows the total ozone record from Antarctica, showing two main features a) the drastic drop in ozone after 1975 and b) the stagnation after 1993, likely as the result of the Montreal Protocol. 

In 1952, the first long-term measurements of the European ozone started in Wahnsdorf near Dresden (in a former observatory of the weather service  

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