No. GRUAN stations will have a variety of instrumentation and observational platforms. The GRUAN challenge will be to homogenize the observations of this diverse set of instruments to establish a consistent data set that can be used for climate research, satellite validation and the characterization of the atmospheric column. However, to achieve homogeneity of observations between different stations identical treatment of observations is a must. This means that observational data have to be analysed to the same detailed level and that uncertainty estimations have to be done consistently across all stations. To verify that observations and uncertainty estimates at different sites using different instrumentation leads to consistent results frequent intercomparisons of these instruments are required. This may be achieved either in dedicated intercomparison campaigns at dedicated sites or routine intercomparisons as part of the observational program.