GCOS Reference Upper-Air Network

The climate reference network

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 May 2019, GRUAN comprises of 26 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

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Two new Antarctic GRUAN sites

We are happy to announce that two Antarctic sites have accepted the invitation by GCOS secretariat to join GRUAN.

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Meeting |

ICM-12: 16-20 November 2020 on Reunion Island

The 12th GRUAN annual Implementation and Coordination Meeting, ICM-12, will be organized 16-20 November 2020.

Article |

AMTD paper Madonna et al. 2020 in review

The following GRUAN-relevant paper was published at AMTD: "Progress in managing the transition from the RS92 to the Vaisala RS41 as the operational…

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GI paper Dirksen et al. 2019 in review

The following GRUAN-relevant paper was published at GID: "Progress in managing the transition from the RS92 to the Vaisala RS41 as the operational…

Document |

Report of the GRUAN ICM-11 released to the public

Report of the Eleventh GCOS Reference Upper-Air Network Implementation and Coordination Meeting (GRUAN ICM-11) published

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AMT paper Jalali et al. 2019

The following GRUAN-relevant paper was published at AMT: "A practical information-centered technique to remove a priori information from lidar…

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GRL paper Naakka et al. 2019

The following GRUAN-relevant paper was published at GRL: "The impact of radiosounding observations on numerical weather prediction analyses in the…

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JAMC paper Sedlar et al. 2019

The following GRUAN-relevant paper was published at JAMC: "A Process-Based Climatological Evaluation of AIRS Level 3 Tropospheric Thermodynamics over…

Document |

Version 2.0 of GRUAN Technical Document 6 published

Version 2.0 of GRUAN Technical Document 6 (GRUAN-TD-6) has been published with title "Global Navigation Satellite System (GNSS) - Precipitable Water…