Ozone–oxygen cycle Ozone–oxygen cycle The ozone–oxygen cycle is the process by which ozone is continually regenerated in Earth's stratosphere, converting ultraviolet radiation (UV) into heat. In 1930 Sydney Chapman resolved the chemistry involved. The process is commonly called the Chapman cycle by atmospheric scientists. Most of the ozone production occurs in the tropical upper stratosphere and mesosphere. The total mass of ozone produced per day over the globe is about 400 million metric tons. The global mass of ozone is relatively constant at about 3 billion metric tons, meaning the Sun produces about 12% of the ozone layer each day. And if
History of the Berlin S-Bahn that were left opened after the strike do include: The 1980 incidents turned media and political attention toward what was left of West Berlin's S-Bahn network. The city government decided to enter negotiations with East Germany, which were finally successful. By contrast, during the same period, services on the S-Bahn in East Berlin were increased and new lines built as housing projects expanded eastward from the city centre. With most of the U-Bahn located in West Berlin, the S-Bahn became the backbone of the East Berlin transit network. The DR has purchased DR Class 270 as a result, where it