Ozone depletion on the surface of the cloud crystals is far different from when it occurs in atmosphere. These conditions have led to ozone hole formation in Antarctica. This hypothesis was decisively confirmed, first by laboratory measurements and subsequently by direct measurements, from the ground and from high-altitude airplanes, of very high concentrations of chlorine monoxide (ClO) in the Antarctic stratosphere. Alternative hypotheses, which had attributed the ozone hole to variations in solar UV radiation or to changes in atmospheric circulation patterns, were also tested and shown to be untenable. Meanwhile, analysis of ozone measurements from the worldwide network of ground-based Dobson
Vienna Convention for the Protection of the Ozone Layer layer. One of the outcomes of the Vienna Convention was the creation of a panel of governmental atmospheric experts known as the Meeting of Ozone Research Managers, which assesses ozone depletion and climate change research and produces a report for the Conference of Parties (COP). Additionally, the COP utilizes the data assessed to suggest new policies aimed at limiting CFC emissions. Currently, the COP meets every three years and coordinates with the timing of a similar meeting rendered under the Montreal Protocol. The Ozone Secretariat functions as an administrator of the COP, Montreal Meeting of Parties (MOP), and Open-Ended Working