Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability

Peak stratospheric chlorofluorocarbon (CFC) andother ozone depleting substance (ODS) concentrations werereached in the mid- to late 1990s. Detection and attributionof the expected recovery of the stratospheric ozone layer inan atmosphere with reduced ODSs as well as efforts to understandthe evolution of stratospheric ozone in the presenceof increasing greenhouse gases are key current research topics.These require a critical examination of the ozone changeswith an accurate knowledge of the spatial (geographical andvertical) and temporal ozone response. For such an examination,it is vital that the quality of the measurements usedbe as high as possible and measurement uncertainties wellquantified.In preparation for the 2014 United Nations EnvironmentProgramme (UNEP)/World Meteorological Organization(WMO) Scientific Assessment of Ozone Depletion, theSPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designedto study and document changes in the global ozoneprofile distribution. This requires assessing long-term ozoneprofile data sets in regards to measurement stability anduncertainty characteristics. The ultimate goal is to establishsuitability for estimating long-term ozone trends to contributeto ozone recovery studies. Some of the data sets havebeen improved as part of this initiative with updated versionsnow available.This summary presents an overview of stratospheric ozoneprofile measurement data sets (ground and satellite based)available for ozone recovery studies. Here we documentmeasurement techniques, spatial and temporal coverage, verticalresolution, native units and measurement uncertainties.In addition, the latest data versions are briefly described (includingdata version updates as well as detailing multipleretrievals when available for a given satellite instrument).Archive location information for each data set is also given.