Maximum accuracy of Umkehr measurements of vertical ozone profiles

A study is made of the maximum feasible accuracy of ozone content determina tion on the basis of Umkehr observations from the world network of ozonomet ric stations equipped with Brewer spectrophotometers. Accuracy improvement by means of optimizing both the algorithm of ozone profile retrieval and UV radiation measurements, which provide the initial data for ozone calculati ons, is investigated. As a result of the theoretical studies, an optimized procedure of Umkehr observations and a new algorithm of vertical ozone prof ile retrieval based on these observations are proposed. Retrieval errors of the new algorithm are smaller than those of the standard network method. F or the lower stratosphere, the error is reduced by a factor of about two. T he optimization of the procedure of observations can give an additional red uction of typical errors to 10-25%.