Attached is a document describing the requirements for GRUAN station regarding the pre-launch procedures for routine soundings with Vaisala RS92 radiosondes. In order to obtain high data quality, ensure long term stability, and to make sure that measurement uncertainties are within the ranges that are reported in the product files, it is important that some ground checks are made before launch in the way described in this document and that the meta-data are reported to the GRUAN lead centre.
FAQ-09: How does GRUAN deal with GPS/Wind measurements where the accuracy is limited by the manufacturer?2009-07-30
GRUAN calls for an uncertainty for every measured parameter. This includes wind measurements as well. Differences in wind and position measurements by different GPS systems have already been noted and this topic is not trivial. Uncertainties as the best estimate for the level of confidence for a given measurement should be established from a detailed understanding of the measurement principle and a detailed understanding of the processing that leads to the final reported measurement. Limitations in the uncertainty estimate imposed by manufacturers should be minimized where possible and verified through independent redundant measurements. In the worst case scenario, uncertainties can only be estimated in the comparison of different systems.