The Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) is an international reference observing network of sites measuring essential climate variables above Earth's surface, designed to fill an important gap in the current global observing system. GRUAN measurements are providing long-term, high-quality climate data records from the surface, through the troposphere, and into the stratosphere. These are being used to determine trends, constrain and calibrate data from more spatially‐comprehensive observing systems (including satellites and current radiosonde networks), and provide appropriate data for studying atmospheric processes. GRUAN is envisaged as a global network of eventually 30-40 sites that, to the extent possible, builds on existing observational networks and capabilities.
GRUAN promotional video
This video provides an excellent overview of the goals and principles of GRUAN and its relation to the current challenges in climate research. You can find this and other public outreach material here.
Status of GRUAN sites
GRUAN is envisaged as a global network of eventually 30-40 measurement sites. To the extent possible, it builds on existing observational networks and capabilities. As at August 2020, GRUAN comprises of 30 sites, 12 of which have been GRUAN certified.
Status of data flow
A comprehensive volume of measurement data has been collected by GRUAN since 2008. The archive includes raw data and related meta-data. For the Vaisala RS92 and the Meisei RS-11G radiosonde, GRUAN Data Products (GDP) have been fully implemented and certified. Further GDPs are in certification process or under development.
Latest news

Campaign
UAII2022 campaign kick-off

Document Metadata
GRUAN Report 5 published

Article
JAMC paper Zhang et al. 2022 published

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Atmosphere paper Rosoldi et al. 2022 published

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MST paper Colombo et al. 2022 published

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AMT paper Hoshino et al. 2022 in review

Meeting
ICM-13 meeting report published

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AMT paper von Rohden et al. 2022 published

Article
AMT paper Ingleby et al. 2022 published

Article
AMT paper Lee et al. 2021 in review

Meeting